Here’s the scenario. A local school district has just released its proposed budget for the upcoming two-year period. Within the 157 page budget document are two pie charts – one for revenues and one for expenditures. The graphic on the left is the actual pie chart for revenues.
Take a look at the graph and see what you think. What has been done well? What would you recommend tweaking?
Of course I have my suggestions – just click here to download my analysis for this pie chart. The last page of this handout even shows an example of how the finished product might look in a budget document.
Today’s graph features data related to grade distributions for 8th grade English. School improvement teams sometimes show grade distributions as a tool to show improvement in a content area. Sometimes a community wants to see the distribution of grades to determine if there is grade inflation. Sometimes college staff looks at distribution of grades for the same reason. Now I am not saying that this data is the right data to use for grade inflation, I’m just noting that this is one way people use this kind of data.
So let’s focus on the graph for grade distributions. As you can likely tell, this graph was part of a presentation. First of all, I’d like to clarify the term, histogram. In a histogram, the bars touch one another. In a bar graph, they do not – so this is really a bar graph. But whatever you call it, the intent is to show the Grade Distribution in 8th Grade English.
Here are a few quick things I want to note about this slide.
Based on the data, it looks as though this school/district used a grading scale in which:
A 91-100 points
B 81-90 points
C 71-80 points
D 51-60 points
F 0-50 points
Since it says on the slide that this data is used to monitor progress, we’d want to see percentages – and not just how many students. Below is how I would present the data in for the distribution of grades in 8th grade English.
- Use a pie chart. A pie chart is perfect for showing the proportions of things in relation to a whole. In this case we can see what percentage of students earned each grade – and this percentage can be compared from one quarter to the next or one grade level to the next.
- Write a title that tells what the data shows. Remember that a good title will tell exactly what the data shows. In this case you can tell that the graph shows the percentage of students who earned each grade, that it’s 8th grade English, that it’s the second quarter of the school year, and you even know what school this data is from.
- Include the percentage with each grade. You can see from the pie chart that forty-two percent (42%) of students earned a B.
- Use contrasting colors to for the labels. When you design this in EXCEL, the default for the labels is black. But a black font does not show well on darker colors, so I made the font white. I also increased the size of the font and made it bold, and then centered the labels within each part of the pie.
- Include the source of the data. One challenge we always have when working with data is comparing it from one year to the next. It’s important to keep track of the source of the data – which specific dataset you used to create a chart or graph – so you compare the same data set from one year to the next. For example, you could place the following within the chart or directly under it:
Data Source: Quarterly 2 Grade Report, Pleasantville Middle School, 2009-2010 School Year. (This is the same report you would use for each Quarter for this and subsequent years – to allow you to compare similar data from one year to the next.)
In this case, just a few changes will make this graph easier to read and interpret – and that’s the purpose for using graphs and charts in the first place.
It’s your turn. You get to make the enrollment graph for the next meeting of the School Board. Yippeee!
Here’s what you’ve come up with. Ugh! You’re just not satisified. But don’t worry.
There’s a fix. Just download the pdf below and you’ll have it in your squeaky-clean, germ-free hands.Fix That Graph, 02