2[item need some revision]
3[relevant but need minor revision]
4[ very relevant]
To obtain content validity index for relevancy and clarity of each item (I-CVIs), the number of those judging the item as relevant or clear (rating 3 or 4) was divided by the number of content experts but for relevancy, content validity index can be calculated both for item level (I-CVIs) and the scale-level (S-CVI). In item level, I-CVI is computed as the number of experts giving a rating 3 or 4 to the relevancy of each item, divided by the total number of experts.
The I-CVI expresses the proportion of agreement on the relevancy of each item, which is between zero and one 3 , 38 and the SCVI is defined as “the proportion of total items judged content valid” 3 or “the proportion of items on an instrument that achieved a rating of 3 or 4 by the content experts”. 28
Although instrument developers almost never give report what method have used to computing the scale-level index of an instrument (S-CVI). 6 There are two methods for calculating it, One method requires u niversal a greement among experts (S-CVI/ UA ), but a less conservative method is ave rages the item-level CVIs (S-CVI/Ave). For calculating them, first, the scale is dichotomized by combining values 3 and 4 together and 2 and 1 together and two dichotomous categories of responses including “ relevant and not relevant ” are formed for each item. 3 , 34 Then, in the universal agreement approach, the number of items considered relevant by all the judges (or number of items with CVI equal to 1) is divided by the total number of items. In the average approach, the sum of I-CVIs is divided by the total number of items. 10 Table 2 provides data for better understanding on calculation CVI and S-CVI by both methods. Data of table has been extracted from judges of our panel about relevancy items of dimension of trust building as a variable (subscale) in measuring construct of patient-centered communication. As the values obtained from both methods might be different, instrument makers should mention the method used for calculating it. 6 Davis proposes that researchers should consider 80 percent agreement or higher among judges for new instruments. 34 Judgment on each item is made as follows: If the I-CVI is higher than 79 percent, the item will be appropriate. If it is between 70 and 79 percent, it needs revision. If it is less than 70 percent, it is eliminated. 39
| | |||
| 14 12 13 12 11 14 12 8 14 | 0 2 1 2 3 0 2 6 0 | 1 0.857 0.928 0.857 0.785 1 0.857 0.571 1 | Appropriate Appropriate Appropriate Appropriate Need for Revision Appropriate Appropriate Eliminated Appropriate |
Number of items considered relevant by all the panelists=3, Number of terms=9, S-CVI/Ave *** or Average of I-CVIs=0.872, S-CVI/UA ** =3/9=.333NOTE: * Item-Content Validity Items, ** Scale-Content Validity Item/Universal agreement, *** Scale-Content Validity Item/Average Number of experts=14, Interpretation of I-CVIs: If the I-CVI is higher than 79 percent, the item will be appropriate. If it is between 70 and 79 percent, it needs revision. If it is less than 70 percent, it is eliminated.
Although content validity index is extensively used to estimate content validity by researchers, this index does not consider the possibility of inflated values because of the chance agreement. Therefore, Wynd et al ., propose both content validity index and multi-rater kappa statistic in content validity study because, unlike the CVI, it adjusts for chance agreement. Chance agreement is an issue of concern while studying agreement indices among assessors, especially when we place four-point scoring within two relevant and not relevant classes. 7 In other words, kappa statistic is a consensus index of inter-rater agreement that adjusts for chance agreement 10 and is an important supplement to CVI because Kappa provides information about degree of agreement beyond chance. 7 Nevertheless, content validity index is mostly used by researchers because it is simple for calculation, easy to understand and provide information about each item, which can be used for modification or deletion of instrument items. 6 , 10
To calculate modified kappa statistic, the probability of chance agreement was first calculated for each item by following formula:
P C = [N! /A! (N -A)!]* . 5 N .
In this formula, N= number of experts in a panel and A= number of panelists who agree that the item is relevant.
After calculating I-CVI for all instrument items, finally, kappa was computed by entering the numerical values of probability of chance agreement (P C ) and content validity index of each item (I-CVI) in following formula:
K= (I-CVI - P C ) / (1- P C ).
Evaluation criteria for kappa is the values above 0.74, between 0.60 and 0.74, and the ones between 0.40 and 0.59 are considered as excellent, good, and fair, respectively. 40
Polit states that after controlling items by calculating adjusted kappa, each item with I-CVI equal or higher than 0.78 would be considered excellent. Researchers should note that, as the number of experts in panel increases, the probability of chance agreement diminishes and values of I-CVI and kappa converge. 10
Requesting panel members to evaluate instrument in terms of comprehensiveness would be the last step of measuring the content validity. The panel members are requested to judge whether instrument items and any of its dimensions are a complete and comprehensive sample of content as far as the theoretical definitions of concepts and its dimensions are concerned. Is it needed to eliminate or add any item? According to members’ judgment, proportion of agreement is calculated for the comprehensiveness of each dimension and the entire instrument. In so doing, the number of experts who have identified instrument comprehensiveness as favorable is divided into the total number of experts. 3 , 37
Face validity answers this question whether an instrument apparently has validity for subjects, patients and/or other participants. Face validity means if the designed instrument is apparently related to the construct underlying study. Do participants agree with items and wording of them in an instrument to realize research objectives? Face validity is related to the appearance and apparent attractiveness of an instrument, which may affect the instrument acceptability by respondents. 11 In principle, face validity is not considered as validity as far as measurement principles are concerned. In fact, it does not consider what to measure, but it focuses on the appearance of instrument. 9 To determine face validity of an instrument, researchers use respondents and experts’ viewpoints. In the qualitative method, face-to-face interviews are carried out with some members of the target groups. Difficulty level of items, desired suitability and relationship between items and the main objective of an instrument, ambiguity and misinterpretations of items, and/or incomprehensibility of the meaning of words are the issues discussed in the interviews. 41
Although content experts play a vital role in content validity, instrument review by a sample of subjects drawn from the target population is another important component of content validation. These individuals are asked to review instrument items because of their familiarity with the construct through direct personal experience. 37 Also they will be asked to identify the items they thought are the most important for them, and grade their importance on a 5-point Likert scale including very important 5 , important 4 , 2 relatively important 3 , slightly important 2 , and unimportant. In quantities method, for calculation item impact score, the first is calculated percent of patients who scored 4 or 5 to item importance (frequency), and the mean importance score of item (importance) and then item impact score of instrument items was calculated by following formula: Item Impact Score= frequency×Importance
If the item impact of an item is equal to or greater than 1.5 (which corresponds to a mean frequency of 50% and an importance mean of 3 on the 5-point Likert scale), it is maintained in the instrument; otherwise it is eliminated. 42
In the one step of our research, which was performed through qualitative content analysis by semi-structured in-depth interview with ten patients with cancer, three family members and seven oncology nurses, the results led to identifying content domain within seven dimensions including trust building, intimacy or friendship, patient activation, problem solving, emotional support, informational support, and spiritual strengthening. Each of these content domains was defined theoretically by combining qualitative study and literature review. In the item generation step, 260 items were generated from these dimensions and they were combined with 32 items obtained from literature and the related instruments. In research group, the items were studied in terms of overlapping and duplication. Finally, 188 items remained for the operational definition of the construct of patient-centered communication, and the preliminary instrument was made by 188 items (pool items) within seven dimensions.
In the second step and after selecting fifteen content experts including the instrument developer experts (four people), cancer research experts (four people),nurse-patient communication experts (three people) and four nurses experienced in cancer care, an expert panel was created for making quantitative and qualitative judgments on instrument items. The panel members were requested thrice to judge on content validity ratio, content validity index, and instrument comprehensiveness. In each round, they were requested to judge on face validity of instrument as well. In each round of correspondences via e-mail or in person, a letter of request was presented, which included study objectives and an account on instrument, scoring method, and required instructions on responding. Theoretical definitions of the construct underlying study, its dimensions, and items of each dimension were also mentioned in that letter. In case no reply was received for the reminder e-mail within a week, a telephone conversation would be made or a meeting would be arranged.
In the first round of judgment, 108 items out of 188 instrument items were eliminated. These eliminated items had content validity ratio lower than 0.49, (according to the expert numbers in our study that was 15, numerical values of the Lawshe table was 0.49) or those which combined to remained items based on the opinion of content experts through editing of item. Table 3 shows a sample of instrument items and CVR calculation method for them.
9 | 0.0667 | Remained | |
5 | -0.333 | Eliminated | |
10 | 0.3333 | Eliminated | |
15 | 0.8667 | Remained | |
9 | 0.2 | Eliminated | |
13 | 0.6 | Remained | |
7 | -0.2 | Eliminated | |
7 | -0.067 | Eliminated | |
13 | 0.6 | Remained |
NOTE: * Number of experts evaluated the item essential, ** CVR or Content Validity Ratio = (N e -N/2)/(N/2) with 15 person at the expert panel (N=15), the items with the CVR bigger than 0.49 remained at the instrument and the rest eliminated.
The remaining items were modified according to the recommendations of panel members in the first round of judgment and for a second time to determine content validity index and instrument modification, the panel members were requested to judge by scoring 1 to 4 on the relevancy and clarity of instrument items according to Waltz and Bussel content validity index. 38
In the second round, the proportion of agreement among panel members on the relevancy and clarity of 80 remaining items of the first round of judgment was calculated.
To obtain content validity index for each item, the number of those judging the item as relevant was divided by the number of content experts (N=14). (As one of the 15 members of panel had not scored some items, the analyses were made by 14 judges). This work was also carried out to clarify the items of the instrument. The agreement among the judges for the entire instrument was only calculated for relevancy according to average and universal agreement approach.
In this round, among the 80 instrument items, 4 items with a CVI score lower than 0.70 were eliminated. Eight items with a CVI between 0.70 and 0.79 were modified (Modification of items was performed according to the recommendation of panel members and research group forums). Two items were eliminated despite having favorable CVI scores, one of which was eliminated due to ethical issues (As some content experts believed that the item “ I often think to death but I don’t speak about it with my nurses .” might cause moral harm to a patient, it was eliminated). On another eliminated item, “ Nurses know that how to communicate with me ”, some experts believed that if that item is eliminated, it would not harm the definition of trust building dimension. According to experts suggestions, an item ( Nurses try that I face no problem during care ) was added in this round. After modification, the instrument containing 57 items was sent to the panel members for the third time to judge on the relevancy, clarity and comprehensiveness of the items in each dimension and need for deletion or addition of the items. In this round, four items had a CVI lower than 0.70, which were eliminated.
The proportion of agreement among the experts was also calculated in this round in terms of comprehensiveness for each dimension of the construct underlying study. Table 4 shows the calculation of I-CVI, S-CVI and modified kappa for items in the instrument for 53 remaining items at the end of the third round of judgment. We also used panel members’ judgment on the clarity of items as well as their recommendations on the modification of items.
| | | |||||
D1: Trust Building | |||||||
D1-1 | 14 | 1 | 6.103 | 1 | Excellent | 14 | 1 |
D1-2 | 12 | 0.857 | 0.022 | 0.85 | Excellent | ||
D1-3 | 12 | 0.857 | 0.022 | 0.85 | Excellent | ||
D1-4 | 12 | 0.857 | 6.103 | 0.85 | Excellent | ||
D1-5 | 12 | 0.857 | 0.022 | 0.85 | Excellent | ||
D1-6 | 14 | 1 | 6.103 | 1 | Excellent | ||
D1-7 | 12 | 0.857 | 6.103 | 0.85 | Excellent | ||
D1-8 | 14 | 1 | 6.103 | 1 | Excellent | ||
D2:Intimacy/Friendship | |||||||
D2-1 | 14 | 1 | 6.103 | 1 | Excellent | 13 | 0.928 |
D2-2 | 14 | 1 | 6.103 | 1 | Excellent | ||
D2-3 | 14 | 1 | 6.103 | 1 | Excellent | ||
D2-4 | 13 | 0.928 | .0008 | 0.928 | Excellent | ||
D2-5 | 14 | 1 | 6.103 | 1 | Excellent | ||
D2-6 | 14 | 1 | 6.103 | 1 | Excellent | ||
D2-7 | 12 | 0.857 | 0.022 | 0.85 | Excellent | ||
D3: Patient activation | |||||||
D3-1 | 12 | 0.857 | 0.022 | 0.85 | Excellent | 14 | 1 |
D3-2 | 13 | 0.928 | 0 | 0.928 | Excellent | ||
D3-3 | 13 | 0.928 | 0 | 0.928 | Excellent | ||
D3-4 | 13 | 0.928 | 0 | 0.928 | Excellent | ||
D3-5 | 14 | 1 | 6.103 | 1 | Excellent | ||
D4: Problem Solving | |||||||
D4-1 | 14 | 1 | 6.103 | 1 | Excellent | 14 | 1 |
D4-2 | 14 | 1 | 6.103 | 1 | Excellent | ||
D4-3 | 12 | 0.857 | 0.022 | 0.85 | Excellent | ||
D4-4 | 12 | 0.857 | 0.022 | 0.85 | Excellent | ||
D4-5 | 13 | 0.928 | 0 | 0.928 | Excellent | ||
D4-6 | 14 | 1 | 6.103 | 1 | Excellent | ||
D4-7 | 14 | 1 | 6.103 | 1 | Excellent | ||
D5: Emotional support | |||||||
D5-1 | 13 | 0.928 | 0 | 0.928 | Excellent | 14 | 1 |
D5-2 | 14 | 1 | 6.103 | 1 | Excellent | ||
D5-3 | 12 | 0.857 | 0.022 | 0.85 | Excellent | ||
D5-4 | 14 | 1 | 6.103 | 1 | Excellent | ||
D5-5 | 13 | 0.928 | 0 | 0.928 | Excellent | ||
D5-6 | 12 | 0.857 | 0.02 | 0.85 | Excellent | ||
D6: Informational support | |||||||
D6-1 | 14 | 1 | 6.103 | 1 | Excellent | 13 | 0.928 |
D6-2 | 13 | 0.928 | 0 | 0.928 | Excellent | ||
D6-3 | 14 | 1 | 6.103 | 1 | Excellent | ||
D6-4 | 13 | 0.928 | 0 | 0.928 | Excellent | ||
D6-5 | 14 | 1 | 6.103 | 1 | Excellent | ||
D6-6 | 14 | 1 | 6.103 | 1 | Excellent | ||
D7:Spirituality strengthening | |||||||
D7-1 | 12 | 0.857 | 0.022 | 0.85 | Excellent | 14 | 1 |
D7-2 | 12 | 0.857 | 0.022 | 0.85 | Excellent | ||
D7-3 | 12 | 0.857 | 0.022 | 0.85 | Excellent | ||
D7-4 | 14 | 1 | 6.103 | 1 | Excellent | ||
D7-5 | 14 | 1 | 6.103 | 1 | Excellent | ||
D7-6 | 12 | 0.857 | 0.022 | 0.85 | Excellent | ||
D7-7 | 12 | 0.857 | 0.022 | 0.85 | Excellent | ||
D7-8 | 13 | 0.928 | 0 | 0.928 | Excellent | ||
D7-9 | 14 | 1 | 6.103 | 1 | Excellent | ||
D7-10 | 13 | 0.928 | 0 | 0.928 | Excellent | ||
D7-11 | 14 | 1 | 6.103 | 1 | Excellent | ||
D7-12 | 13 | 0.928 | 0 | 0.928 | Excellent | ||
D7-13 | 13 | 0.928 | 0 | 0.928 | Excellent | ||
D7-14 | 13 | 0.928 | 0 | 0.928 | Excellent | ||
53 Items | S-CVI/Ave= 0.939S-CVI/UN= 0.434 | Agreement on total comprehensiveness=14Comprehensiveness of entire instrument=1 |
NOTE : * I-CVI: item-level content validity index, ** p c (probability of a chance occurrence) was computed using the formula: p c = [N! /A! (N -A)!] * .5 N where N= number of experts and A= number of panelists who agree that the item is relevant. Number of experts=14, *** K(Modified Kappa) was computed using the formula: K= (I-CVI- P C )/(1- P C ). Interpretation criteria for Kappa, using guidelines described in Cicchetti and Sparrow (1981): Fair=K of 0.40 to 0.59; Good=K of 0.60 to 0.74; and Excellent=K>0.74
A sample of 10 people of patients with cancer who had a long-term history of hospitalization in oncology wards (lay experts) was requested to judge on the importance, simplicity and understandability of items in an interview with one of the members of research team. According to their opinions, to make some items more understandable, objective examples were included in an item. “For instance, the item “N urses try not to cause any problem for me ” was changed into “ During care (e.g. preparation an intravenous line), Nurses try not to cause any problem for me ”. The item “Care decisions are made without paying attention to my needs ” was changed to “ Nurses didn’t ask my opinion about care(e.g. time of care or type of interventions) ”. In addition the quantitative analysis was also performed as calculating impact score of each item. Nine items had item impact score less than 1.5 and they were eliminated from the final instrument for preliminary test. Finally, at the end of the content validity and face validity process, our instrument was prepared with seven dimensions and 44 items for the next steps and doing the rest of psychometric testing.
Present paper demonstrates quantities indices for content validity a new instrument and outlines them during design and psychometrics of patient centered communication measuring instrument. It should be said that validation is a lengthy process, in the first-step of which, the content validity should be studied and the following analyses should be directed include reliability evaluation (through internal consistency and test-retest), construct validity (through factor analysis) and criterion-related validity. 37
Some limitations of content validity studies should be noted, Experts’ feedback is subjective; thus, the study is subjected to bias that may exist among the experts. If content domain is not well identified, this type of study does not necessarily identify content that might have been omitted from the instrument. However, experts are asked to suggest other items for the instrument, which may help minimize this limitation. 11
Content validity study is a systematic, subjective and two-stage process. In the first stage, instrument design is carried out and in the second stage, judgment/quantification on instrument items is performed and content experts study the accordance between theoretical and operational definitions. Such process should be the leading study in the process of making instrument to guarantee instrument reliability and prepare a valid instrument in terms of content for preliminary test phase. Validation is a lengthy process, in the first step of which, the content validity should be studied. The following analyses should be directed include reliability evaluation (through internal consistency and test-retest), construct validity by factor analysis and criterion-related validity. Meanwhile, we showed that although content validity is a subjective process, it is possible to objectify it.
Understanding content validity is important for clinician groups and researchers because they should realize if the instruments they use for their studies are suitable for the construct, population under study, and socio-cultural background in which the study is carried out, or there is a need for new or modified instruments.
Training on content validity study helps students, researchers, and clinical staffs better understand, use and criticize research instruments with a more accurate approach.
In general, content validity study revealed that this instrument enjoys an appropriate level of content validity. The overall content validity index of the instrument using a conservative approach (universal agree- ment approach) was low; however, it can be advocated with respect to the high number of content experts that makes consensus difficult and high value of the S-CVI with the average approach, which was equal to 0.93.
The researchers appreciate patients, nurses, managers, and administrators of Ali-Nasab and Shahid Ayatollah Qazi Tabatabaee hospitals. Approval to conduct this research with no. 5/74/474 was granted by the Hematology and Oncology Research Center affiliated to Tabriz University of Medical Sciences.
None to be declared.
The authors declare no conflict of interest in this study.
Research validity in surveys relates to the extent at which the survey measures right elements that need to be measured. In simple terms, validity refers to how well an instrument as measures what it is intended to measure.
Reliability alone is not enough, measures need to be reliable, as well as, valid. For example, if a weight measuring scale is wrong by 4kg (it deducts 4 kg of the actual weight), it can be specified as reliable, because the scale displays the same weight every time we measure a specific item. However, the scale is not valid because it does not display the actual weight of the item.
Research validity can be divided into two groups: internal and external. It can be specified that “internal validity refers to how the research findings match reality, while external validity refers to the extend to which the research findings can be replicated to other environments” (Pelissier, 2008, p.12).
Moreover, validity can also be divided into five types:
1. Face Validity is the most basic type of validity and it is associated with a highest level of subjectivity because it is not based on any scientific approach. In other words, in this case a test may be specified as valid by a researcher because it may seem as valid, without an in-depth scientific justification.
Example: questionnaire design for a study that analyses the issues of employee performance can be assessed as valid because each individual question may seem to be addressing specific and relevant aspects of employee performance.
2. Construct Validity relates to assessment of suitability of measurement tool to measure the phenomenon being studied. Application of construct validity can be effectively facilitated with the involvement of panel of ‘experts’ closely familiar with the measure and the phenomenon.
Example: with the application of construct validity the levels of leadership competency in any given organisation can be effectively assessed by devising questionnaire to be answered by operational level employees and asking questions about the levels of their motivation to do their duties in a daily basis.
3. Criterion-Related Validity involves comparison of tests results with the outcome. This specific type of validity correlates results of assessment with another criterion of assessment.
Example: nature of customer perception of brand image of a specific company can be assessed via organising a focus group. The same issue can also be assessed through devising questionnaire to be answered by current and potential customers of the brand. The higher the level of correlation between focus group and questionnaire findings, the high the level of criterion-related validity.
4. Formative Validity refers to assessment of effectiveness of the measure in terms of providing information that can be used to improve specific aspects of the phenomenon.
Example: when developing initiatives to increase the levels of effectiveness of organisational culture if the measure is able to identify specific weaknesses of organisational culture such as employee-manager communication barriers, then the level of formative validity of the measure can be assessed as adequate.
5. Sampling Validity (similar to content validity) ensures that the area of coverage of the measure within the research area is vast. No measure is able to cover all items and elements within the phenomenon, therefore, important items and elements are selected using a specific pattern of sampling method depending on aims and objectives of the study.
Example: when assessing a leadership style exercised in a specific organisation, assessment of decision-making style would not suffice, and other issues related to leadership style such as organisational culture, personality of leaders, the nature of the industry etc. need to be taken into account as well.
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Published on September 27, 2024 by Emily Heffernan, PhD .
When choosing how to measure something, you must ensure that your method is both reliable and valid . Reliability concerns how consistent a test is, and validity (or test validity) concerns its accuracy.
Reliability and validity are especially important in research areas like psychology that study constructs . A construct is a variable that cannot be directly measured, such as happiness or anxiety.
Researchers must carefully operationalize , or define how they will measure, constructs and design instruments to properly capture them. Ensuring the reliability and validity of these instruments is a necessary component of meaningful and reproducible research.
Reliability | Validity | |
---|---|---|
Whether a test yields the same results when repeated. | How well a test actually measures what it’s supposed to. | |
Is this measurement consistent? | Is this measurement accurate? | |
A test can be reliable but not valid; you might get consistent results but be measuring the wrong thing. | A valid test must be reliable; if you are measuring something accurately, your results should be consistent. | |
A bathroom scale produces a different result each time you step on it, even though your weight hasn’t changed. The scale is not reliable or valid. | A bathroom scale gives consistent readings (it’s reliable) but all measurements are off by 5 pounds (it’s not valid). |
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Understanding reliability and validity, reliability vs validity in research, validity vs reliability examples, frequently asked questions about reliability vs validity.
Reliability and validity are closely related but distinct concepts.
Reliability is how consistent a measure is. A test should provide the same results if it’s administered under the same circumstances using the same methods. Different types of reliability assess different ways in which a test should be consistent.
Type of reliability | What it assesses | Example |
---|---|---|
Does a test yield the same results each time it’s administered (i.e., is it consistent)? | Personality is considered a stable trait. A questionnaire that measures introversion should yield the same results if the same person repeats it several days or months apart. | |
Are test results consistent across different raters or observers? If two people administer the same test, will they get the same results? | Two teaching assistants grade assignments using a rubric. If they each give the same paper a very different score, the rubric lacks interrater reliability. | |
Do parts of a test designed to measure the same thing produce the same results? | Seven questions on a math test are designed to test a student’s knowledge of fractions. If these questions all measure the same skill, students should perform similarly on them, supporting the test’s internal consistency. |
Validity (more specifically, test validity ) concerns the accuracy of a test or measure—whether it actually measures the thing it’s supposed to. You provide evidence of a measure’s test validity by assessing different types of validity .
Type of test validity | What it assesses | Example |
---|---|---|
Does a test actually measure the thing it’s supposed to? Construct validity is considered the overarching concern of test validity; other types of validity provide evidence of construct validity. | A researcher designs a game to test young children’s self-control. However, the game involves a joystick controller and is actually measuring motor coordination. It lacks construct validity. | |
Does a test measure all aspects of the construct it’s been designed for? | A survey on insomnia probes whether the respondent has difficulty falling asleep but not whether they have trouble staying asleep. It thus lacks content validity. | |
Does a test seem to measure what it’s supposed to? | A scale that measures test anxiety includes questions about how often students feel stressed when taking exams. It has face validity because it clearly evaluates test-related stress. | |
Does a test match a “gold-standard” measure (a criterion) of the same thing? The criterion measure can be taken at the same time ( ) or in the future ( ). | A questionnaire designed to measure academic success in freshmen is compared to their SAT scores (concurrent validity) and their GPA at the end of the academic year (predictive validity). A strong correlation with either of these measures indicates criterion validity. | |
Does a test produce results that are close to other tests of related concepts? | A new measure of empathy correlates strongly with performance on a behavioral task where participants donate money to help others in need. The new test demonstrates convergent validity. | |
Does a test produce results that differ from other tests of unrelated concepts? | A test has been designed to measure spatial reasoning. However, its results strongly correlate with a measure of verbal comprehension skills, which should be unrelated. The test lacks discriminant validity. |
Test validity concerns the accuracy of a specific measure or test. When conducting experimental research , it is also important to consider experimental validity —whether a true cause-and-effect relationship exists between your dependent and independent variables ( internal validity ) and how well your results generalize to the real world ( external validity ).
In experimental research, you test a hypothesis by manipulating an independent variable and measuring changes in a dependent variabl e. Different forms of experimental validity concern how well-designed an experiment is. Mitigating threats to internal validity and threats to external validity can help yield results that are meaningful and reproducible.
Type of experimental validity | What it measures | Example |
---|---|---|
Does a true cause-and-effect relationship exist between the independent and dependent variables? | A researcher evaluates a program to treat anxiety. They compare changes in anxiety for a treatment group that completes the program and a control group that does not. However, some people in the treatment group start taking anti-anxiety medication during the study. It is unclear whether the program or the medication caused decreases in anxiety. Internal validity is low. | |
Can findings be generalized to other populations, situations, and contexts? | A survey on smartphone use is administered to a large, randomly selected sample of people from various demographic backgrounds. The survey results have high external validity. | |
Does the experiment design mimic real-world settings? This is often considered a subset of external validity. | A research team studies conflict by having couples come into a lab and discuss a scripted conflict scenario while an experimenter takes notes on a clipboard. This design does not mimic the conditions of conflict in relationships and lacks ecological validity. |
Though reliability and validity are theoretically distinct, in practice both concepts are intertwined.
Reliability is a necessary condition of validity: a measure that is valid must also be reliable. An instrument that is properly measuring a construct of interest should yield consistent results.
However, a measure can be reliable but not valid. Consider a clock that’s set 5 minutes fast. If checked at noon every day, it will consistently read “12:05.” Though the clock yields reliable results, it is not valid: it does not accurately reflect reality.
Because reliability is a necessary condition of validity, it makes sense to evaluate the reliability of a measure before assessing its validity. In research, validity is more important but harder to measure than reliability. It is relatively straightforward to assess whether a measurement yields consistent results across different contexts, but how can you be certain a measurement of a construct like “happiness” actually measures what you want it to?
Reliability and validity should be considered throughout the research process. Validity is especially important during study design, when you are determining how to measure relevant constructs. Reliability should be considered both when designing your study and when collecting data—careful planning and consistent execution are key.
Reliability and validity are both important when conducting research. Consider the following examples of how a measure may or may not be reliable and valid.
Casey can choose a different measure in an attempt to improve the reliability and validity of her study.
Even though the measure in the previous example is reliable, it lacks validity. Casey must try a different approach.
Psychology and other social sciences often involve the study of constructs —phenomena that cannot be directly measured—such as happiness or stress.
Because we cannot directly measure a construct, we must instead operationalize it, or define how we will approximate it using observable variables. These variables could include behaviors, survey responses, or physiological measures.
Validity is the extent to which a test or instrument actually captures the construct it’s been designed to measure. Researchers must demonstrate that their operationalization properly captures a construct by providing evidence of multiple types of validity , such as face validity , content validity , criterion validity , convergent validity , and discriminant validity .
When you find evidence of different types of validity for an instrument, you’re proving its construct validity —you can be fairly confident it’s measuring the thing it’s supposed to.
In short, validity helps researchers ensure that they’re measuring what they intended to, which is especially important when studying constructs that cannot be directly measured and instead must be operationally defined.
A construct is a phenomenon that cannot be directly measured, such as intelligence, anxiety, or happiness. Researchers must instead approximate constructs using related, measurable variables.
The process of defining how a construct will be measured is called operationalization. Constructs are common in psychology and other social sciences.
To evaluate how well a construct measures what it’s supposed to, researchers determine construct validity . Face validity , content validity , criterion validity , convergent validity , and discriminant validity all provide evidence of construct validity.
Test validity refers to whether a test or measure actually measures the thing it’s supposed to. Construct validity is considered the overarching concern of test validity; other types of validity provide evidence of construct validity and thus the overall test validity of a measure.
Experimental validity concerns whether a true cause-and-effect relationship exists in an experimental design ( internal validity ) and how well findings generalize to the real world ( external validity and ecological validity ).
Verifying that an experiment has both test and experimental validity is imperative to ensuring meaningful and generalizable results.
An experiment is a study that attempts to establish a cause-and-effect relationship between two variables.
In experimental design , the researcher first forms a hypothesis . They then test this hypothesis by manipulating an independent variable while controlling for potential confounds that could influence results. Changes in the dependent variable are recorded, and data are analyzed to determine if the results support the hypothesis.
Nonexperimental research does not involve the manipulation of an independent variable. Nonexperimental studies therefore cannot establish a cause-and-effect relationship. Nonexperimental studies include correlational designs and observational research.
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Methodology
Published on February 17, 2022 by Pritha Bhandari . Revised on June 22, 2023.
Construct validity is about how well a test measures the concept it was designed to evaluate. It’s crucial to establishing the overall validity of a method.
Assessing construct validity is especially important when you’re researching something that can’t be measured or observed directly, such as intelligence, self-confidence, or happiness. You need multiple observable or measurable indicators to measure those constructs or run the risk of introducing research bias into your work.
What is a construct, what is construct validity, types of construct validity, how do you measure construct validity, threats to construct validity, other interesting articles, frequently asked questions about construct validity.
A construct is a theoretical concept, theme, or idea based on empirical observations. It’s a variable that’s usually not directly measurable.
Some common constructs include:
Constructs can range from simple to complex. For example, a concept like hand preference is easily assessed:
A more complex concept, like social anxiety, requires more nuanced measurements, such as psychometric questionnaires and clinical interviews.
Simple constructs tend to be narrowly defined, while complex constructs are broader and made up of dimensions. Dimensions are different parts of a construct that are coherently linked to make it up as a whole.
As a construct, social anxiety is made up of several dimensions.
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Construct validity concerns the extent to which your test or measure accurately assesses what it’s supposed to.
In research, it’s important to operationalize constructs into concrete and measurable characteristics based on your idea of the construct and its dimensions.
Be clear on how you define your construct and how the dimensions relate to each other before you collect or analyze data . This helps you ensure that any measurement method you use accurately assesses the specific construct you’re investigating as a whole and helps avoid biases and mistakes like omitted variable bias or information bias .
When designing or evaluating a measure, it’s important to consider whether it really targets the construct of interest or whether it assesses separate but related constructs.
It’s crucial to differentiate your construct from related constructs and make sure that every part of your measurement technique is solely focused on your specific construct.
There are two main types of construct validity.
Convergent validity is the extent to which measures of the same or similar constructs actually correspond to each other.
In research studies, you expect measures of related constructs to correlate with one another. If you have two related scales, people who score highly on one scale tend to score highly on the other as well.
Conversely, discriminant validity means that two measures of unrelated constructs that should be unrelated, very weakly related, or negatively related actually are in practice.
You check for discriminant validity the same way as convergent validity: by comparing results for different measures and assessing whether or how they correlate.
How do you select unrelated constructs? It’s good to pick constructs that are theoretically distinct or opposing concepts within the same category.
For example, if your construct of interest is a personality trait (e.g., introversion), it’s appropriate to pick a completely opposing personality trait (e.g., extroversion). You can expect results for your introversion test to be negatively correlated with results for a measure of extroversion.
Alternatively, you can pick non-opposing unrelated concepts and check there are no correlations (or weak correlations) between measures.
You often focus on assessing construct validity after developing a new measure. It’s best to test out a new measure with a pilot study, but there are other options.
It’s important to recognize and counter threats to construct validity for a robust research design. The most common threats are:
Experimenter expectancies, subject bias.
A big threat to construct validity is poor operationalization of the construct.
A good operational definition of a construct helps you measure it accurately and precisely every time. Your measurement protocol is clear and specific, and it can be used under different conditions by other people.
Without a good operational definition, you may have random or systematic error , which compromises your results and can lead to information bias . Your measure may not be able to accurately assess your construct.
Experimenter expectancies about a study can bias your results. It’s best to be aware of this research bias and take steps to avoid it.
To combat this threat, use researcher triangulation and involve people who don’t know the hypothesis in taking measurements in your study. Since they don’t have strong expectations, they are unlikely to bias the results.
When participants hold expectations about the study, their behaviors and responses are sometimes influenced by their own biases. This can threaten your construct validity because you may not be able to accurately measure what you’re interested in.
You can mitigate subject bias by using masking (blinding) to hide the true purpose of the study from participants. By giving them a cover story for your study, you can lower the effect of subject bias on your results, as well as prevent them guessing the point of your research, which can lead to demand characteristics , social desirability bias , and a Hawthorne effect .
If you want to know more about statistics , methodology , or research bias , make sure to check out some of our other articles with explanations and examples.
Research bias
Construct validity is about how well a test measures the concept it was designed to evaluate. It’s one of four types of measurement validity , which includes construct validity, face validity , and criterion validity.
There are two subtypes of construct validity.
When designing or evaluating a measure, construct validity helps you ensure you’re actually measuring the construct you’re interested in. If you don’t have construct validity, you may inadvertently measure unrelated or distinct constructs and lose precision in your research.
Construct validity is often considered the overarching type of measurement validity , because it covers all of the other types. You need to have face validity , content validity , and criterion validity to achieve construct validity.
Statistical analyses are often applied to test validity with data from your measures. You test convergent validity and discriminant validity with correlations to see if results from your test are positively or negatively related to those of other established tests.
You can also use regression analyses to assess whether your measure is actually predictive of outcomes that you expect it to predict theoretically. A regression analysis that supports your expectations strengthens your claim of construct validity .
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Bhandari, P. (2023, June 22). Construct Validity | Definition, Types, & Examples. Scribbr. Retrieved September 24, 2024, from https://www.scribbr.com/methodology/construct-validity/
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Content validity evaluates how well an instrument covers all relevant parts of the construct it aims to measure. Learn the difference between content validity and construct validity, see examples from various fields, and follow a step-by-step guide to calculate content validity.
Content validity is the degree to which an assessment instrument covers the construct it is meant to measure. Learn how to establish content validity using expert opinion, focus groups, surveys, and numerical methods.
Learn about the four main types of validity in research: construct, content, face and criterion. Criterion validity is the most difficult to establish in quantitative research, as it requires comparing the test results with external criteria.
Content validity is the extent to which a measurement instrument covers the intended content domain or construct. Learn about different methods, steps, and threats to content validity, and see examples of content validity in research.
Content validity evaluates how well a test or questionnaire covers all relevant parts of a construct. Learn how to measure content validity with experts, formulas, and examples from psychology research.
Content validity is how well a research instrument measures a construct that is not directly measurable, such as health or happiness. Learn how to use expert data, content validity ratio, and content validity index to evaluate content validity.
Learn how to measure content validity, the degree to which a test or assessment instrument covers the full range of topics or dimensions related to the construct. See examples, methods, and critical values for the content validity ratio.
Survey Research Methods. A. Fink, in International Encyclopedia of Education (Third Edition), 2010 Content Validity. Content validity refers to the extent to which a measure thoroughly and appropriately assesses the skills or characteristics it is intended to measure. For example, a survey researcher who is interested in developing a measure of mental health has to first define the concept ...
Content validity refers to the extent to which the items on a test are fairly representative of the entire domain the test seeks to measure. This entry discusses origins and definitions of content validation, methods of content validation, the role of [Page 239] content validity evidence in validity arguments, and unresolved issues in content ...
Qualitative research to establish and support content validity should have a strong and documentable scientific basis and be conducted with the rigor required of all robust research (Brod et al., 2009; Lasch et al., 2010; Magasi et al., 2012; Patrick et al., 2011a, 2011b).An interviewer who is well versed in managing qualitative research and who understands the importance of accurately ...
Content validity refers to the degree to which an assessment instrument is relevant to, and representative of, the targeted construct it is designed to measure. It involves domain definition, domain representation, and domain relevance, and can be evaluated using judgmental or statistical methods.
Learn how to use content analysis to identify patterns in recorded communication, such as texts, speeches, or social media posts. Find out the advantages, disadvantages, and steps of this research method.
content validity. Methods This paper provides an overview of the current state of knowledge regarding qualitative research to establish content validity based on the scientific methodo-logical literature and authors' experience. Results Conceptual issues and frameworks for qualitative interview research, developing the interview discussion
Learn about the concept of validity in psychology research, which refers to the accuracy and reliability of tests and measurements. Explore different types of validity, such as internal, external, content, criterion, face, and construct validity, with examples and definitions.
Learn about validity, the accuracy and truthfulness of research, and its types: internal, external, construct, content, criterion, and face validity. Find out how to ensure validity in research and its applications and limitations.
The higher the content validity of a test, the more accurate is the measurement of the target construct (e.g., de Von et al., 2007). While we all know how important content validity is, it tends to receive little attention in assessment practice and research (e.g., Rossiter, 2008; Johnston et al., 2014). In many cases, test developers assume ...
Some content validity measurement methods, such as interrater reliability (IRR), Aiken's validity, content validity ratio (CVR), and content validity index (CVI), were also used.
The argument presented is that content validity requires a mixed methods approach since data are developed through qualitative and quantitative methods that inform each other. ... Brod M., Tesler L., Christensen T. (2009). Qualitative research and content validity: Developing best practices based on science and experience. Quality of Life ...
Content validity ratio (Lawshe's method) One approach to achieving content validity includes a panel of experts considering the relevance of individual items within an instrument. The content validity ratio (CVR), an item statistic originally suggested by Lawshe (1975), is one of the most widely used methods for quantifying content validity.
The qualitative research methods can also be applied to determine the variables and concepts of the pertinent construct. 29 The qualitative data collected in the interview with the respondents familiar with concept help enrich ... In qualitative content validity method, content experts and target group's recommendations are adopted on ...
5. Sampling Validity (similar to content validity) ensures that the area of coverage of the measure within the research area is vast. No measure is able to cover all items and elements within the phenomenon, therefore, important items and elements are selected using a specific pattern of sampling method depending on aims and objectives of the ...
Reliability and validity are concepts used to evaluate the quality of research. They indicate how well a method, technique, or test measures something. Learn the difference, types and examples of reliability and validity in quantitative research.
Reliability vs Validity | Examples and Differences. Published on September 27, 2024 by Emily Heffernan, PhD. When choosing how to measure something, you must ensure that your method is both reliable and valid.Reliability concerns how consistent a test is, and validity (or test validity) concerns its accuracy.. Reliability and validity are especially important in research areas like psychology ...
Construct validity is about how well a test measures the concept it was designed to evaluate. It's one of four types of measurement validity. Learn about the types, methods, and threats of construct validity.