Eight items were selected on the basis that they covered a range of difficulties and their patterns of responses closely conformed to the Rasch model's expectations in terms of discriminating between test takers' ability measures (i.e., infit mean square for the items were 0.9 to 1.1).
However, in Upington where summer temperatures are considerably higher than in Johannesburg and where there is a greater frequency of very hot days, a broader range of difficulties and ill health effects was reported.
The authors also insist on four other conditions to facilitate learning i.e. feedback, repetitive practice, opportunities for the trainee to engage in the practice of medical skills across a wide range of difficulties and multiple learning strategies.
These numbers would be sufficient to create short forms for specific ranges of difficulty and would populate the extremes with approximately as many items per standard deviation as in the current core item set.
Secondly, future research should seek to compare the basic mannequins currently used for training to training on high-fidelity mannequins that provide a range of difficulty levels, and to assess whether this latter training would be more effective in preparing students for real life practice.
Turning to the difficulty measure of the test, the 39 items showed a wide range of difficulty (Table 3), and they represented nearly six levels of difficulty (i.e., 5.73 strata, with a reliability coefficient of.94).
Item discrimination and difficulty were calculated for each question, both pre- and postinstruction, to represent the range of difficulty of the items and to measure the gains that students made over the semester.
