SAT vs. ACT. The recent changes. What can we infer with some data.
Since 2001, the national average participation rate has been dominated by ACT. In recent years, there has been some changes.
From 2017 to 2018, data have shown a shift and an increased of participation from ACT to SAT, as seem below in Figure 1 and Figure 2.
The box plot comparison shows 2018 SAT median higher than 2017 with higher 75th percentile. In fact, its average increased to 44.3% compare to previous 38.6%. Simultaneously, 2018 ACT median is lower than 2017 with it average decreased from 65% to 62%. Thus, SAT and ACT has a inverse relationship, as seem in Figure 3. It made sense as states will choice one test and not both (Figure 3).
What cause such change? We wondered. To answer this curiosity, we will need to look into States which recently converted to SAT. But first, lets look at the geographical relationship among SAT and ACT to understand where the conversion comes from.
In Figure 4, the Mid of United States dominates the ACT with 25 of 33 States, while West coast has 2 of 5 States and East Coast 4 of 14 States.
In Figure 5, SAT popularity is among the coastal states, West and East Coast. West Cost has 3 of 5 States, East Coast has 12 of 14 States while the Mid has 6 of 33 States.
When we compare Figure 4 to Figure 6 , Mid still dominated ACT but its total count reduced from 25 to 23. The difference went into SAT 2018, as seem in Figure 7, where the total count of Mid had increased while the the coastal States remained the same.
The 2 States that converted into SAT for 2018 were Colorado and Illinois. They followed Michigan who converted to SAT in 2016. Upon further research, their decision to change came from their State government and College Board reached a better contracts with more free resources to the students, such as free mock exams and free online resources.
This raises another thought. Since the conversion related to cost, does it mean ACT cost more than SAT, or vice versa? Given the average income in 2017 for West Coast was around $74k, East Coast $78k and Mid at about $60k, we can assume ACT cost lower than SAT for most States. Given this assumption, in order to convert a state like Mississippi with participation rate for SAT at 3% and an average income at around $43K, College Board will need to diligently negotiate a contract with free resource that equivalent or better than the contract with ACT. In order to better understand this interference, it will required another research on its own.
As we can see, exploring and analyzing data can give us many inferences and questions. Answers to those questions and thoughts will allow us to make better decision in the future. Thus, this is where data science comes in.