How do I use these tests of reliability? When we examine a construct in a study, we choose one of a number of possible ways to measure that construct [see the section on Constructs in quantitative researchif you are unsure what constructs are, or the difference between constructs and variables].
Validity refers to how well a test measures what it is purported to measure. Why is it necessary?
While reliability is necessary, it alone is not sufficient. For a test to be reliable, it also needs to be valid.
For example, if your scale is off by 5 lbs, it reads your weight every day with an excess of 5lbs. The scale is reliable because it consistently reports the same weight every day, but it is not valid because it adds 5lbs to your true weight.
It is not a valid measure of your weight. Types of Validity 1. Face Validity ascertains that the measure appears to be assessing the intended construct under study. The stakeholders can easily assess face validity. If the stakeholders do not believe the measure is an accurate assessment of the ability, they may become disengaged with the task.
If a measure of art appreciation is created all of the items should be related to the different components and types of art. If the questions are regarding historical time periods, with no reference to any artistic movement, stakeholders may not be motivated to give their best effort or invest in this measure because they do not believe it is a true assessment of art appreciation.
Construct Validity is used to ensure that the measure is actually measure what it is intended to measure i. The experts can examine the items and decide what that specific item is intended to measure.
Students can be involved in this process to obtain their feedback. The questions are written with complicated wording and phrasing. It is important that the measure is actually assessing the intended construct, rather than an extraneous factor. Criterion-Related Validity is used to predict future or current performance - it correlates test results with another criterion of interest.
If a physics program designed a measure to assess cumulative student learning throughout the major. The new measure could be correlated with a standardized measure of ability in this discipline, such as an ETS field test or the GRE subject test.
The higher the correlation between the established measure and new measure, the more faith stakeholders can have in the new assessment tool. Formative Validity when applied to outcomes assessment it is used to assess how well a measure is able to provide information to help improve the program under study.
If the measure can provide information that students are lacking knowledge in a certain area, for instance the Civil Rights Movement, then that assessment tool is providing meaningful information that can be used to improve the course or program requirements.
Sampling Validity similar to content validity ensures that the measure covers the broad range of areas within the concept under study. Not everything can be covered, so items need to be sampled from all of the domains.
When designing an assessment of learning in the theatre department, it would not be sufficient to only cover issues related to acting.
Other areas of theatre such as lighting, sound, functions of stage managers should all be included. The assessment should reflect the content area in its entirety.
What are some ways to improve validity?
Make sure your goals and objectives are clearly defined and operationalized. Expectations of students should be written down. Match your assessment measure to your goals and objectives.
Additionally, have the test reviewed by faculty at other schools to obtain feedback from an outside party who is less invested in the instrument.
Get students involved; have the students look over the assessment for troublesome wording, or other difficulties. If possible, compare your measure with other measures, or data that may be available.
Standards for educational and psychological testing. Methods in Behavioral Research 7th ed.Validity encompasses the entire experimental concept and establishes whether the results obtained meet all of the requirements of the scientific research method.
For example, there must have been randomization of the sample groups and appropriate care and diligence shown in . pdf version of this page.
Part I: The Instrument. Instrument is the general term that researchers use for a measurement device (survey, test, questionnaire, etc.).To help distinguish between instrument and instrumentation, consider that the instrument is the device and instrumentation is the course of action (the process of developing, testing, and using the device).
Do the subjects tell the truth? The reliability of self-report data is an Achilles’ heel of survey research. For example, opinion polls indicated that more than 40 percent of Americans attend church every week. Statistical validity describes whether the results of the research are accurate. Reliability describes whether the results are repeatable.
For example, the researcher would want to know that the successful tutoring sessions work in a different school district. Reliability and Validity in Research;. reliability and validity as used in quantitative research are discussed as a way of providing a springboard to examining what these two terms mean and how they can .
Practical Assessment Research & Evaluation, Vol 11, No 10 2 Ross, Self-Assessment assessment and focuses attention on its consequential validity.