getCorrectResponsesPattern LMS implementation issues for a single correct response #222
Description
When using SCORM 2004, it has been found that some LMSs (SuccessFactors), will raise a 406 - Data Model Element Type Mismatch, when a single correct response value is recorded for cmi.interactions.n.correct_responses.n.pattern. In these cases, the LMS seems to enforce the <min>[:]<max> format, ignoring the following from the SCORM standards:
The numeric correct response is represented as two numbers with an optional decimal point. The numbers may be used to express an inclusive range for the correct response. If the numbers are the same, then a single number is specified as the correct response [1].
The SCORM standards slightly cloud this due to the following example:
SetValue(“cmi.interactions.0.correct_responses.0.pattern”, “3.14159[:]3.14159”)
This is an example of a numeric interaction where the correct responses collection has one pattern. The API method call indicates that the correct response is a real number exactly equal to “3.14159”.
xAPI is fairly clear on this matter with the following:
A range of numbers represented by a minimum and a maximum delimited by [:]. Where the range does not have a maximum or does not have a minimum, that number is omitted but the delimiter is still used. E.g. [:]4 indicates a maximum for 4 and no minimum. Where the correct response or learner's response is a single number rather than a range, the single number with no delimiter MAY be used.
Other LMSs, including SCORM Cloud, correctly accept the singular correct response, but in order to negate this issue for LMSs that haven't followed that part of the implementation, we should probably switch to using the correct response for both the minimum and maximum values regardless.