Jose Has Developed a Test That Has Poor Reliability. He Can Seek to Increase Reliability by:
EXPLORING RELIABILITY IN Bookish ASSESSMENT
Written by Colin Phelan and Julie Wren, Graduate Administration, UNI Function of Academic Assessment (2005-06)
Reliability is the caste to which an assessment tool produces stable and consistent results.
Types of Reliability
- Exam-retest reliability is a measure of reliability obtained past administering the same test twice over a catamenia of fourth dimension to a group of individuals. The scores from Time i and Fourth dimension 2 tin can then be correlated in order to evaluate the examination for stability over time.
Case: A test designed to assess student learning in psychology could be given to a group of students twice, with the second assistants peradventure coming a calendar week later on the first. The obtained correlation coefficient would indicate the stability of the scores.
- Parallel forms reliability is a measure of reliability obtained past administering different versions of an assessment tool (both versions must contain items that probe the same construct, skill, knowledge base, etc.) to the same group of individuals. The scores from the two versions tin can and so be correlated in order to evaluate the consistency of results beyond alternate versions.
Example: If you wanted to evaluate the reliability of a disquisitional thinking assessment, you might create a large set of items that all pertain to critical thinking and and so randomly divide the questions upwardly into ii sets, which would represent the parallel forms.
- Inter-rater reliability is a measure of reliability used to assess the degree to which different judges or raters agree in their assessment decisions. Inter-rater reliability is useful because human being observers will not necessarily translate answers the same way; raters may disagree as to how well certain responses or material demonstrate knowledge of the construct or skill being assessed.
Case: Inter-rater reliability might be employed when different judges are evaluating the degree to which fine art portfolios meet certain standards. Inter-rater reliability is especially useful when judgments can be considered relatively subjective. Thus, the use of this blazon of reliability would probably be more likely when evaluating artwork equally opposed to math problems.
- Internal consistency reliability is a measure of reliability used to evaluate the degree to which different exam items that probe the same construct produce similar results.
- Average inter-particular correlation is a subtype of internal consistency reliability. It is obtained by taking all of the items on a test that probe the same construct (eastward.g., reading comprehension), determining the correlation coefficient for each pair of items, and finally taking the average of all of these correlation coefficients. This final pace yields the average inter-particular correlation.
- Split-half reliability is another subtype of internal consistency reliability. The process of obtaining split-half reliability is begun by �splitting in one-half� all items of a exam that are intended to probe the aforementioned area of knowledge (e.g., World War 2) in order to form ii �sets� of items. The entire test is administered to a grouping of individuals, the total score for each �set� is computed, and finally the split-half reliability is obtained by determining the correlation between the ii total �set� scores.
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, information technology besides needs to be valid. For example, if your calibration is off by 5 lbs, information technology reads your weight every mean solar day with an excess of 5lbs. The scale is reliable because it consistently reports the same weight every twenty-four hours, just it is not valid because it adds 5lbs to your true weight. It is non a valid measure of your weight.
Types of Validity
1. Face Validity ascertains that the measure appears to be assessing the intended construct under report. The stakeholders can easily assess face validity. Although this is not a very �scientific� type of validity, information technology may be an essential component in enlisting motivation of stakeholders. If the stakeholders practise not believe the measure is an accurate assessment of the ability, they may become disengaged with the task.
Example: If a measure of fine 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 whatever artistic movement, stakeholders may non be motivated to give their best attempt or invest in this measure considering they exercise not believe it is a true assessment of art appreciation.
2. Construct Validity is used to ensure that the measure is actually measure what information technology is intended to mensurate (i.eastward. the construct), and not other variables. Using a panel of �experts� familiar with the construct is a way in which this type of validity can be assessed. The experts can examine the items and decide what that specific item is intended to measure. Students can exist involved in this process to obtain their feedback.
Example: A women�south studies programme may blueprint a cumulative assessment of learning throughout the major. The questions are written with complicated wording and phrasing. This can cause the test inadvertently becoming a test of reading comprehension, rather than a test of women�s studies. It is important that the measure is actually assessing the intended construct, rather than an extraneous gene.
3. Criterion-Related Validity is used to predict hereafter or electric current performance - it correlates test results with some other criterion of interest.
Example: If a physics program designed a measure to assess cumulative pupil learning throughout the major. The new measure could exist correlated with a standardized measure of ability in this discipline, such as an ETS field test or the GRE discipline exam. The college the correlation between the established mensurate and new measure, the more faith stakeholders can have in the new assessment tool.
iv. 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 plan under study.
Example: When designing a rubric for history 1 could assess student�s cognition across the subject. If the measure out tin can provide information that students are defective knowledge in a certain area, for instance the Civil Rights Movement, then that cess tool is providing meaningful information that tin be used to improve the course or program requirements.
five. Sampling Validity (similar to content validity) ensures that the measure covers the broad range of areas within the concept under study. Not everything tin can exist covered, so items demand to exist sampled from all of the domains. This may need to be completed using a panel of �experts� to ensure that the content expanse is adequately sampled. Additionally, a panel can aid limit �expert� bias (i.e. a test reflecting what an individual personally feels are the most important or relevant areas).
Example: When designing an assessment of learning in the theatre section, information technology would not exist 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 cess should reflect the content area in its entirety.
What are some ways to meliorate validity?
- Make certain 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, accept 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; accept the students look over the cess for troublesome wording, or other difficulties.
- If possible, compare your measure out with other measures, or data that may exist available.
References
American Educational Enquiry Association, American Psychological Association, &
National Quango on Measurement in Education. (1985). Standards for educational and psychological testing . Washington, DC: Authors.
Cozby, P.C. (2001). Measurement Concepts. Methods in Behavioral Research (7th ed.).
California: Mayfield Publishing Company.
Cronbach, L. J. (1971). Test validation. In R. L. Thorndike (Ed.). Educational
Measurement (second ed.). Washington, D. C.: American Council on Education.
Moskal, B.M., & Leydens, J.A. (2000). Scoring rubric development: Validity and
reliability. Practical Assessment, Research & Evaluation, 7(ten). [Available online: http://pareonline.internet/getvn.asp?5=7&n=10].
The Center for the Enhancement of Teaching. How to improve examination reliability and
validity: Implications for grading. [Available online: http://october.sfsu.edu/assessment/evaluating/htmls/improve_rel_val.html].
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