Ploting the Data

Yesterday I looked at SAT scores in Maryland by county and income and for the incoming freshman classes of the public four-year institutions. Today I take a brief look at SAT scores by county and race/ethnicity from the same dataset published by the Maryland State Department of Education. I made a dot plot using Datawrapper with all the race/ethnicity categories available in the data set as well as “all students”. To be honest, the chart looks very busy and is rather hard to read. I changed the color scheme to reds and oranges to aid with distinguishing the categories, but it only helped a little. I could choose custom colors for each group, and would if I was intending to show this data to a wider audience, but since this is primarily for my own exploration of the data I decided I did not have the energy to make those choices today. I did decide to highlight the “all student” category to help with readability a bit.

An alternative visualization, and the one I have seen used at State Board of Education meetings, is a grouped bar chart. While I think that would work for smaller numbers of counties or race/ethnicities, I think that it is worst than the dot plot for a large amount of data. However, I may explore this visualization in the future.

SAT SCores by county and Race/Ethnicity

It is hard to draw any conclusions from this data. For one thing, I am unsure if this data represents public school students or all students who took the test from that county. For another thing, not all students take the SAT and different local school systems have different policies about pushing students to take the SAT.

Howard County stands out as having very high scores, for students of all races. From the data, I do not know if Howard County encouraged only high-performing students to take the SAT. I would be surprised if that was the case, but it is a possibility. Since there is information about the number of students that took the test, I might be able to infer the policy from that data or I might look at their website to see if they have a SAT policy.

Note: I likely will not be posting for a while as I will be on vacation.


I have been reading through the Maryland Higher Education Commission’s Annual Data Book 2021. I am interested to see if I can learn any new insights by exploring different visualizations of the data. I am also teaching myself how to use data visualization/graphing software. Today I am taking a look at SAT scores statistics published in the databook as well as additional SAT scores published by the Maryland State Department of Education. The populations for all of these datasets are slightly different.

SAT Scores of Entering for High School Seniors 2020

According to the databook, the mean combined evidence-based reading and writing score and math for Maryland high school seniors in 2020 was 1029, slightly less than the nationwide mean of 1051. I have read in the past this is because a higher percentage of students in Maryland take the SAT than nationally, but I will have to find a citation that is true.

SAT Scores By COunty

On the Maryland Report Card, the Maryland State Department of Education publishes data about students. As part of the "college readiness data", average SAT scores are published. In addition to an average for all students from the local school system, the scores are disaggregated by a number of subpopulations including by low-income students, that is those eligible for free or reduced price meals. Low-income students scored lower on the SAT than all students in every county. However, the average scores were nearly identical for students from Dorchester County. At the SEED school, where almost all students are low-income, low-income students scored higher than all students.

There is a large range of scores between counties and between low-income students and all students in most counties. Howard County has the highest average score for all students and the second-highest average score., after Carroll County, for low-income students. In fact, low-income students from Carroll and Howard counties had a higher average score than the average score for all students from 14 counties, Baltimore City, and the SEED school.

I plan to examine the data for more subpopulations in the future. Including the best way to visualize the data.

SAT SCores of Entering Freshmen

The MHEC databook publishes the average, 25th percentile, and 75th percentile SAT scores of entering freshmen at the public four-year institutions. Institutions submit aggregated data on average SAT scores for all incoming freshmen. Some institutions do not require SAT scores for admission. Institutional score ranges are based upon those scores that were used as a basis for admitting students to the institution.

This chart shows the SAT scores of entering freshmen for the University of Maryland, College Park from the 25th to the 75th percentile