So I recently came across some national student testing data and was asked to analysis them. Both the ACT and SAT are nationally recognized standardized tests. All US colleges and universities accept scores from either the ACT or SAT. This means two things. First, there is no advantage in one test over the other. Second, you can apply to the same schools, regardless of which test you take. So, the chance of students decide to take ACT or SAT will be the same? Let’s look at the nationwide participation rate.
As shown in Figure 1, ACT and SAT participation rate is strong contrast around central US. Red color means the participation rate is near 100 % and blue color means the participation rate near 0 %. What cause this kind of distribution? Some states are starting to make the ACT/SAT mandatory and have already provided the ACT/SAT free of charge to all juniors. Will this mean every student is mandatory to take ACT/SAT even though they don’t want to attend colleges or universities? If they don’t intend to be a college or university student, why would they want to spend a bunch of time preparing tests. How will this scenario change the ACT/SAT scores?
As shown in Figure 2, the heatmap shows the correlations between ACT participation rate, ACT total score, SAT participation rate and SAT total score in every state. Dark color means positive correlation between two features and light color means negative correlation. ACT participation rate is negative correlation to total ACT score and SAT participation rate, but positive correlation to total SAT score. This means the higher ACT participation rate, the lower ACT score and SAT participation rate, but higher total SAT score.
Let us look closely at the states with low SAT participation and see what their ACT test distribution are like. Figure 3 shows the 23 states in blue where SAT participation rate is less than 20 %. 17 out of these 23 states actually make ACT mandatory which means the ACT participation rate of these states are 100 %.
On the left-hand panel of Figure 4 shows ACT participation rate of these 23 states in blue dots. The blue dots tell us that in these 23 states where ACT participation rate are greater than 60 %, the total score of most of these states are lower than average (green dash line). However, as shown in the right-hand panel of Figure 4, these 23 states get highest SAT total score nationwide.
Because there are more states that make ACT mandatory than those that make SAT mandatory. We can see that there are more states, 23 to be exact, with low SAT participation rate (the 23 blue dots under the gray 20% dash line on the right-hand panel of Figure 4) than states with low ACT participation rate (3 dots, representing 3 states, under gray dash line on the left-hand panel of Figure 4). However, how do we explain the overall outcome that in both tests, states with lower participation rate actually get higher total score?
Let us focus on the 23 states that make ACT an mandatory test, which represented as blue dots in Figure 4. No doubt the ACT participation rate is high as it is mandatory, but if we look at the same blue dots on the right-panel, it shows that the the fewer participants from the same 23 states who took the SAT tests actually score higher. This might be because those students who also took the SAT test are more ambitious. They take a second entrance exam to make them more stand out.
We all know that taking both ACT/SAT is not only time-consuming but also super stressful, even for students who are really good at exams. Therefore, why don’t we make an uni entrance exam and let every student take it? This will leave more time for student to enjoy their high school and save money and resources for setting up multiple exams.
