Through the first semester of 2017 facilitators started using the prefix and suffix functionality for numeric questions (released March 2017).

The use of prefixes and suffixes on numeric questions greatly reduces input errors by participants or students.

Previously, in order to clarify the required answer(s) facilitators have relied on entering the required units in the question text.  Despite including the required units in the question text (eg: ” give your answer in kilograms of…”), some students make mistakes simply because they had failed to read these clarifying instructions carefully.

By using prefixes and suffixes, the response form provided to the participant is enhanced by the contextual information (such as units), preventing these simple errors.

For example….

In response to a question such as “What is the force exerted by a weight of 5o0kg on the Earth’s surface? Enter your answer in N”, a student might be tempted to answer:

  • 4900 (correct),
  • 4900 N (correct, but superfluous text will result in the answer being marked wrong),
  • 4.9 (correct answer in kN but failed to follow instructions)

The incidence of simple errors by students who understand the underlying concept, will be reduced by specifying the suffix as in the following figure on the right.

Comparison of Participant views of question with and without suffix

(Left): Participant view of question without suffix. (Right): Participant view of question with suffix.


Suffix "N" added

Suffix “N” added to question using in Question Editor

Prefix and suffix fields are determined by the facilitator in the question editor. They determine what a participant sees “before” and “after” (ie left and right of) the entry field in their browser.  The above simple example of a suffix (“N”) is shown at right.

Common choices for prefix might be ‘US$’, ‘£’, etc while choices for suffixes might be ‘km’, ‘cm”, “kg”, “hours” etc.

Prefix and suffixes can be any string of text up to five characters long, so “apples” or “minutes” are equally valid suffixes; “September” must be shortened to “Sept” however as seen on the following example…..

Question involving both a prefix and a suffix

Question involving both a prefix and a suffix, as seen on participant device.

A prefix and/or suffix applying to the desired answer may be specified by the facilitator for any numeric question.  Any text is acceptable: If a desired symbol or character is not available directly from your keyboard, an easy work-around is to use another software package such as Word to search and insert the desired symbol into a document, or search to find the symbol in a page on the internet; select and copy the symbol, and then paste it into the prefix or suffix field in the question editor.  Prefixes ” λ= “, “£”, “€”, “¥” and suffixes “Ω” are good examples.