I was looking at a property. Next to the Zillow page, the school score was displayed. An 8 out of 10. It looked good. But when I asked a friend who lives in the same neighborhood, the reaction was different. That school is a bit questionable these days. It was a moment when the numbers and the local reputation didn't match. I couldn't decide which one to trust.

We need to understand why this happens. The school scores shown on Zillow or Redfin are mostly ratings given by a nonprofit organization called GreatSchools. They are simply displayed on a scale from 1 to 10, with higher numbers being better. However, this score does not reflect just one test score. It compresses various indicators into a single number, so if you don't know the composition, it can lead to misunderstandings.

According to GreatSchools' official explanation, high school ratings are created by combining four indicators: test scores, academic growth, college readiness, and equity. If the school has all the data, achievement, growth, and college readiness each account for 33% of the score. College readiness looks at SAT and ACT scores, graduation rates, and participation rates in advanced courses like AP or IB. The equity indicator examines how evenly performance, attendance, and discipline data are distributed among various student groups, such as low-income or disabled students. This means that just having a high average for the entire student body does not guarantee a high score.

Let's also discuss how to actually verify these scores. If you search for a school name on the GreatSchools website, you will find separate detailed scores for test scores, growth, college readiness, and equity below the overall score. By clicking on several years of data, you can also check whether the rating is trending upward or downward. If you only look at the overall score, you might miss these details.

The reason why the growth indicator is particularly important is that schools with many high-achieving students can easily receive high ratings based solely on test scores. In contrast, growth measures how much students have improved compared to the previous year, so schools that started with lower scores can still receive good evaluations if they are consistently improving. This means that even if two schools have the same overall score, the content behind those scores can be entirely different.

Looking at elementary schools in the St. Louis area, this disparity is clearly evident. Avery Elementary School and Reed Elementary School both received a perfect score of 10 from GreatSchools. In contrast, within the same St. Louis area, Woodward Elementary School scored 5, and Adams Elementary School only scored 2. This indicates that there can be such a large gap between schools even within the same city. According to GreatSchools.org.

Therefore, you should not make decisions based on just one score. The score is merely a snapshot of a specific year. You also need to consider whether the rating has been trending upward or downward in recent years. It's important to check the student-to-teacher ratio as well. A lower number means that teachers have more opportunity to pay attention to each student. Reading parent reviews in the school review section can also reveal aspects like commuting conditions or after-school programs that are not reflected in the scores.

And there is one more thing you must check. You need to know exactly which school district your desired home address falls into, that is, the school boundary. School district boundaries can often vary even within the same zip code, sometimes divided by just one road. The school information displayed on real estate websites may differ from the actual assigned school.

If you are a family moving to St. Louis from another state, it's important to consider not just school scores but also property taxes and insurance rates. Tax and insurance conditions can vary by state and county, so estimating based on the standards of the state you previously lived in may lead to unexpected differences.

Here are the items to check in practice:

• Recent trends in GreatSchools ratings over the last 3-5 years
• Student-to-teacher ratio, school reviews, and parent feedback
• The exact school name and boundary assigned to the address

Online scores are a starting point, not a conclusion. School districts change frequently, so before signing a contract, be sure to verify the assigned school for that address directly through the school district's website or office. This article is not investment or legal advice, and it is recommended to consult with real estate and related professionals before making any actual contracts.