If you have looked at a League Table then you have used ‘data’.
If you want to create a shortlist, or maybe narrow down your options, then using data is a good choice. It is usually best to go to the source of the data, although sometimes this can be less user-friendly than secondary sites which pass on the source data.
However, data needs to be up-to-date and meaningful, for it to be of use in that process.
There is not really any point in using data which is out of date. Yearly data is of great use in analysing schools as performance data is published at this frequency. Historic data then gives a comparison over time, to understanding if a school is maintaining their performance.
Taking Ofsted as an example – School Performance Tables – contains Ofsted data but the ‘latest’ is from the middle of 2015. This website has other good points about it though.
If you wanted a ranking of schools then it would be fair to expect all schools to be included!
Locrating is a user friendly website, however, the ranking it uses for Secondary schools is based on A-level results (in this case Average Point Score per pupil) . As you can see from the picture below, Millthorpe School, for example, appears near the bottom of the list because it doesn’t have a sixth form, however it is a reasonable school based on results.
Ensure the data you are using is up-to-date so you are getting the latest picture. If there are rankings involved then confirm that the methodology used is meaningful to your needs.