Blog — September 2, 2020

The Time Crunch: How much time should candidates be given to take an exam?

by Alex Diaz

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Posted on: September 2, 2020 Written by: Alex Diaz Read time: 8 min. Posted in:

When developing an assessment, two major decisions a credentialing organization needs to make are: how many items will be on the exam, and how much time candidates will be given to complete the exam. These decisions can have a large impact on fairness and validity. Once an exam has been administered, candidates often report running out of time and that the assessment was unfair. How can organizations investigate and address these concerns?

In the credentialing field, assessments almost always have time limits. Although these are often set in order to provide standardized administration conditions, it is important to allow a candidate enough time to complete an assessment without undue time pressures. If the allocated time is too short, this could undermine validity (Lu & Sireci, 2007). 

Tests are classified as being either speed or power tests (Gulliksen, 1950). The difference between these two types impacts what is called “test speededness,” or the rate at which an exam is completed, as well as the correctness of candidate responses.

Speed Tests

Although a speed test is designed so that the questions are so easy that examinees would rarely give a wrong answer, it is also so long that no candidate can complete the entire test in the allotted time. As a result, candidates are judged by how far they get while taking the test before running out of time. This approach is commonly used in IQ tests and other types of aptitude tests.

Power Tests

A pure power test is a test in which all items should be attempted, and the candidate’s performance is judged by the correctness of their responses. Although most credentialing examinations are power tests by design, time limits are generally used. The question then becomes, “does the use of a time limit change a credentialing exam from being a power test to a speed test?

Whenever a test involves a time limit, the rate at which a candidate moves through the items on the exam will affect their performance. A small percentage of candidates, no matter how much time is given, will not complete an exam. As a result, most examinations contain a mixture of speed and power components (Rindler, 1979). 

There are several ways in which unintended test speededness may undermine test validity. For example, when speededness is unintended, candidate scores can be lowered due to factors such as anxiety and stress. Test speededness can also negatively impact content validity, because some scored items are not attempted. This is problematic if the unattempted items fit into one or more content domains. 

Therefore, it is important to demonstrate that a test is not overly affected by speededness. There are several statistical indices that are available to assess speededness using a single administration approach.

Methods of assessing speededness

Educational Testing Service (ETS) provides three guidelines to assess test speededness (Schaeffer, Reese, Steffen, McKinley & Mills, 1993; Swineford, 1973). A test is speeded when less than 80% of candidates complete the exam, less than 100% of candidates reach 75% of the test, and/or the ratio of “not reached variance” to “total score variance” is greater than 0.15. The “not reached variance” represents the variance of the number of items left unanswered following the last item for which the candidate responded. This statistic is divided by the “total score” variance in order to obtain the “not reached” to “total score” variance ratio. 

The three criteria above are based on the notion that a candidate will run out of time at the end of the exam and fail to respond to items that have not been reached. There are, however, two other scenarios to consider. Near the end of an exam, a candidate may realize that there is insufficient time to finish the test. In one scenario, the candidate might accelerate their work rate and skip items that would take too much time. This candidate would then have a sporadic response pattern near the end of the exam. In another scenario, upon recognizing that time is running out, the candidate might respond randomly to all remaining items (Oshima, 1994).

Modification #1: Correcting for sporadic responding

Under the original method, a candidate’s stopping point is identified as the point at which the candidate did not respond to any further items. However, it is possible that a candidate who is feeling significant time pressure might begin to answer questions sporadically. As a result, the original method should be modified. The candidate’s stopping point could be identified as the point where the candidate last responded to at least three consecutive questions.

The following is an illustration based on a 200-item test:

Question190191191193194195196197198199200
Response412211

Original method: The candidate is considered to have finished the exam.

Refined method: The candidate reached question 193 and did not complete the exam.

Modification #2: Correcting for random responding

Most candidates see a drop in performance near the end of an exam that is likely due to fatigue. However, a candidate who is under significant time pressure may choose to either respond to questions very quickly without fully reading or comprehending the material or answer in a completely random manner. In some cases, a candidate may respond to every single question on an exam, but may respond randomly near the end. 

To account for this, candidate performance on the first and last 25 scored items of the exam can be compared. Candidates who display a statistically significant (p<0.01) drop in performance during the last 25 questions of the exam can be deemed to have run out of time. This is in contrast to the original method that would have considered this candidate to have finished the exam.

What can prevent an exam from being overly speeded?

Decisions related to the number of items on an exam and the time allocated to candidates to complete the exam should not be taken lightly. Significant research should be conducted first. This may include looking at historical response patterns for the exam or looking at comparable assessments. In the case of an entry-to-practice exam, it would also be helpful to look at policies in place at the educational/training level.

Some exams contain experimental/pilot items that are presented to candidates but do not count toward their total score. These items are typically presented throughout the exam. If speededness is a concern, one strategy is to place such experimental/pilot items at the end of an exam (without indicating to candidates that the items are experimental/pilot items). This way, if candidates run out of time, their exam scores will not be impacted because the experimental/pilot items were not attempted. 

Many exam blueprints provide guidelines on the number of items from different competency categories. Items can then be presented in two ways: 1) items can be presented by competency category, or 2) items from different competency categories can be interspersed. If speededness were a concern, the latter approach should be used. This way, if candidates are unable to complete an exam, content validity impacts can be mitigated because items do not systematically come from one specific area.

In addition, many exam blueprints contain targets for taxonomy levels such as knowledge, application and critical thinking. In general, knowledge questions take less time to respond to compared to critical thinking questions. Therefore, taxonomy should also be considered when setting the blueprint.

Finally, from an exam administration perspective, candidates should be given frequent timing updates throughout the exam (e.g., “one hour left”) and a clock should be visible. This will prevent candidates from losing track of their progress and running out of time.

What if speededness is detected?

Evidence of speededness on an exam form may require a credentialing organization to revisit an exam blueprint to modify the number of questions on the exam and/or the time given to candidates to take the exam.  

However, this does not address what to do with the candidates who took the exam that displayed evidence of excessive speededness. This is exacerbated in situations where numerous candidates are reporting that the time for completion was insufficient. What can be done to make the assessment fair for these candidates?

One solution is to exclude the last handful of questions on the exam. For example, on a 200-item exam, the speededness analysis can be redone following deletion of the last ten questions. Does the revised 190-item exam still display evidence of speededness? If yes, it may be necessary to remove additional items.

References:

Gulliksen, H. (1950). Theory of mental tests. New York: John Wiley.

Kolen, M.J., & Brennan, R.L. (2004). Test equating, scaling, and linking. Methods and practices (2ed.). New York: Springer-Verlag.

Oshima, T.C. (1994). The effect of speededness on parameter estimation in item response theory. Journal of Educational Measurement, 31 (3), 200-219.

Rindler, S.E. (1979). Pitfalls in assessing test speededness. Journal of Educational Measurement, 16 (4), 261-270.

Schaeffer, G.A., Reese, C.M., Steffen, M. McKinley, R.L., & Mills, C.N. (1993). Field test of a computer-based GRE General Test (ETS Report No. RR-93-07). Princeton, NJ: Educational Testing Service.

Stafford, R.E. (1971). The speed quotient: A new descriptive statistic for tests. Journal of Educational Measurement, 8, 275-278.

Swineford, F. (1973). An assessment of the Kuder-Richardson Formula (20) reliability estimate for moderately speeded tests. Paper presented at the annual meeting of the National Council of Measurement in Education (New Orleans, Louisiana, February 28, 1973).

Yu, L., & Sireci, S.G. (2007). Validity issues in test speededness. Educational Measurement: Issues and Practice, Winter 2007.