There was a family contemplating between Demarest and nearby Old Tappan. Both areas had good reviews on school review sites. However, they were confused about why the school scores on real estate sites showed that the two areas were grouped under the same school district.

First, let's clarify the school scores listed on Zillow and Redfin. These scores are ratings given by a nonprofit organization called GreatSchools. They range from 1 to 10, and to put it simply, this number is not just a reflection of a single test score but a composite score that combines various indicators.

According to the official description, high school ratings are composed of four components: test scores, academic growth, college readiness, and equity. If all data is available, achievement, growth, and college readiness each contribute 33% to the overall score. If college readiness is unfamiliar, think of it this way: it is a measure that combines SAT and ACT scores, graduation rates, and participation rates in AP and IB programs. Equity looks at whether performance is evenly distributed among various student groups, such as low-income or disabled students.

If you search for a school name on the GreatSchools site, you will find these four detailed scores listed separately below the overall score. By clicking on several years of data, you can also see whether the ratings are trending upward or downward.

The growth component is particularly important. 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 a school that started with lower scores can still receive a good evaluation if it shows a consistent upward trend. Even if two schools have the same overall score, their actual compositions can be very different.

Demarest is part of the Northern Valley school district and is consolidated with the Old Tappan campus at the high school level. Northern Valley Regional High School at Old Tappan received a GreatSchools score of 9. T. Baldwin Demarest Elementary School, located in Demarest, also received a score of 9, according to GreatSchools.org. This is why the two areas are grouped under the same school district. While elementary schools are separate for each town, high schools are operated as a consolidated system.

When comparing the two areas side by side, the star ratings on review sites and the GreatSchools scores do not always point in the same direction. Reviews are subjective evaluations based on individual parent experiences, while GreatSchools scores are the result of objective data combined from test scores and college readiness. Both should be considered together to get a complete picture.

Another factor to consider is the recent trend of ratings and the student-to-teacher ratio. Scores are just a snapshot of a moment in time, so whether they are trending upward or downward can provide more meaningful information.

In areas like Northern Valley, where school ratings are high, property prices often reflect this. For families moving from out of state, it is important to consider property tax burdens alongside school ratings to help ensure a stable home purchase. Tax rates can vary by town.

In areas like Demarest, where the operational systems for elementary and high schools differ, it is also important to remember that there may be more than one school to check based on your child's age group. If you currently have young children, you should look at elementary school ratings, while if you have children who will soon be in middle or high school, you should also consider the consolidated high school ratings.

Finally, here are the items to check:

• GreatSchools ratings and recent trends, parent reviews
• Student-to-teacher ratio
• Actual assigned schools based on property address; elementary and high schools may differ

The Northern Valley school district is a consolidated system that includes not only Demarest but also students from Closter and Harrington Park, so it can be helpful to look at changes in school ratings in neighboring towns as well.

Scores and reviews are just reference materials. School district boundaries change frequently, so please verify the assigned school for the specific address before signing a contract. This article is not investment or legal advice, and it is recommended to consult with a professional before making any actual agreements.