Station statistical analysis

The station statistic analysis report is available for written exams and displays item performance information as well as insight into candidate response behaviours.

Running the station statistic analysis report

• Step 1 of 4

  Navigate to your exam then Set standard and View reports.

  

• Step 2 of 4

  Click Create new report and Station statistic analysis.

  

• Step 3 of 4

  Select the date for which you wish to run the report. You can also optionally give the report a name. Select the items you wish to include in the report (SHIFT+select or CMD/CTRL+select for multi-selection). Alternatively do not select any items in the list to include everything. 

  

  Only item types that have selectable answer options will be shown in this list

  Click Save to commit.

• Step 4 of 4

  Click Preview to view the output.

  

  You can also export a copy of this report to PDF.

Report output

The report output is shown in the image below:

• Metric	Description
  33% item discrimination	Item discrimination is the degree to which students with high overall exam scores also got a particular item correct. The station statistic analysis uses a 33% cohort to calculate the discrimination. getting all correct answers and sorting them in order selecting the top third correct answers and the bottom third correct answers subtracting the bottom from the top
  Point biserial	The item discrimination index is a point-biserial correlation coefficient. Its possible range is -1.00 to 1.00. A positive result indicates that there is a high correlation between higher-performing candidates giving a correct response to the item.
  Correct answer	The correct answer key
  Facility	The difficulty of the item. This is calculated as the sum of candidate scores / the sum of maximum possible scores.

• Metric	Description
  Answer frequency	The proportion of the cohort that chose each response option. N/A refers to unanswered questions.

• Metric

  Description

  Quintile graph

  Candidates are split into 5 groups based on their overall test scores. The chart shows the proportion of candidates in each group (with the top 20% group to the left and the bottom 20% group to the right) who answered the question correctly. A “steps down” graph would indicate that the candidate's performance on the question is closely correlated with their overall performance. The inverse is true if the graph “steps up”.