Looking at raw marks can provide useful information about the performance of students, but it is sometimes helpful to look at marks on a different scale. This chapter looks at some of these.
For instance, z-scores and stanines make it easier to compare results on different tests if either the total marks or the difficulty of the tests are different. Z-scores and stanines can be obtained from internal analysis of a single set of marks, or by reference to a larger population of marks (such as a national distribution). In the latter case, percentiles can also be reported.
The final section of the chapter describes other methods of scaling marks that are intended for increasing or decreasing the raw marks when the assessment was too easy or too hard. This is sometimes necessary to conform to external guidelines.