The Gradiator: spreadsheet to choose grade boundaries based on grade distributions

If you are like me, you do not enjoy the task of trying to decide grade boundaries for assessments. If you are a Head of Department, you may be responsible for deciding grades that go on reports, which are sent home to parents. It is vital these are representative of the attainment of the students.

I have made this spreadsheet to make the process less painful.

Simply enter a suitable distribution of grades into the ‘Curve to fit’ section (I use the distribution of results from the previous cohort’s public examinations), then copy the percentage scores for the students into the ‘Scores (%)’ section. The Grade boundaries appear under ‘Boundaries’. Some schools use subgrades (dividing each grade into three), so subgrade boundaries are also produced (listed in ascending and descending order, to suit your preference of index-match or vlookup formulas)

Of course, it can be a pain writing your own formulas to generate the grades, so the formulas are also produced, which can be copied and pasted (as text!) into your own spreadsheet. Don’t forget to change the cell to which the formula refers under ‘Cell’.

If you need to see how it works, I’ve uploaded a YouTube video to demonstrate.

HOW IT WORKS: the spreadsheet assumes a normal distribution for all data. The normal distribution standard deviation and mean are determined from the data you enter under ‘Curve to fit’, which is then used to generate matching grade boundaries for the ‘Scores (%)’ data, which should produce a similar spread of results. Doing all that statistical crunching manually can take far too long, so I wrote this spreadsheet to speed the process up.