Field Test Studies: Taking your items for a test drive
Posted by Austin Fossey
In large-scale assessment, a significant amount of work goes into writing items before a participant ever sees them. Items are drafted, edited, reviewed for accuracy, checked for bias, and usually rewritten several times before they are ready to be deployed. Despite all this work, a true test of an item’s performance will come when it is first delivered to participants.
Even though we work so hard to write high-quality items, some bad items may slip past our review committees. To be safe, most large-scale assessment programs will try out their items with a field test.
A field test delivers items to participants under the same conditions used in live testing, but the items do not count toward the participants’ scores. This allows test developers and psychometricians to harvest statistics that can be used in an item analysis to flag poorly performing items.
There are two methods for field testing items. The first method is to embed your new items into an assessment that is already operational. The field test items will not count against the participants’ scores, but the participants will not know which items are scored items and which items are field test items.
The second method is to give participants an assessment that includes only field test items. The participants will not receive a score at the end of the assessment since none of the items have yet been approved to be used for live scoring, though the form may be scored later once the final set of items has been approved for operational use.
In their chapter in Educational Measurement (4 th ed.), Schmeiser and Welch explain that embedding the items into an operational assessment is generally preferred. When items are field tested in an operational assessment, participants are more motivated to perform well on the items. The item data are also collected while the operational assessment is being delivered, which can help improve the reliability of the item statistics.
When participants take an assessment that only consists of field test items, they may not be motivated to try as hard as they would in an operational assessment, especially if the assessment will not be scored. However, field testing a whole form’s worth of items will give you better content coverage with the items so that you have more items that can be reviewed in the item analysis. If field testing an entire form, Shmeiser and Welch suggest using twice as many items as you will need for the operational form. Many items may need to be discarded or rewritten as a result of the item analysis, so you want to make sure you will still have enough to build an operational form at the end of the process.
Since the value of field testing items is to collect item statistics, it is also important to make sure that a representative sample of participants responds to the field test items. If the sample of participant responses is too small or not representative, then the item statistics may not be generalizable to the entire population.
Questionmark’s authoring solutions allow test developers to field test items by setting the item’s status to “Experimental.” The item will still be scored, and the statistics will be
generated in the Item Analysis Report, but the item will not count toward the participant’s final score.
Setting an item’s status to “Experimental” in Questionmark Live so that it can be field tested.