It is true that public schools have to test their students, so using a similar metric is a reasonable, relative comparison between public and private schools. (theconversation.com)
By relative comparison to ants we build tiny structures of little complexity. (dotearth.blogs.nytimes.com)
From the context of relative comparison of temperatures from one period to another — it should be noted that «raw» temperature data are not pristine instrumental observations that are more «real» than the adjusted data. (bom.gov.au)