How many years of SLAS/NAS data should I look at, to find areas of focus?

When determining how many years of SLAS (State Learning Achievement Survey) or NAS (National Achievement Survey) data to look at in order to identify areas of focus, it’s important to consider the frequency and nature of these assessments. NAS, being a national-level survey, typically takes place only once every 3-4 years and employs random sampling methods. As a result, it’s not possible to conduct a cohort-based analysis of performance over time using NAS data. Therefore, when relying on NAS data, it’s recommended to primarily focus on the most recent NAS report, as it provides the latest snapshot of student achievement on a national scale.

On the other hand, if you have access to SLAS data that is collected more frequently and covers a larger sample of students, a cohort-based analysis can be valuable. This approach involves examining data from the same group of students over a series of years, which can help identify trends and patterns in learning achievement. By conducting a cohort-based analysis with SLAS data, you can gain insights into the longitudinal performance of students and pinpoint areas that require consistent attention and improvement.

In summary, the choice of how many years of data to consider depends on the availability and nature of the data, with SLAS data lending itself to cohort-based analysis while NAS data should primarily be approached with the latest report due to its infrequent, random sampling nature.