How can we express to our school board that high-stakes tests are just one piece of information that typically measures multiple standards, rather than the mastery of specific skills we are teaching? Our school board, and the general public

How can we express to our school board that high-stakes tests are just one piece of information that typically measures multiple standards, rather than the mastery of specific skills we are teaching? Our school board, and the general public, want to know if students are "on grade level" or not, and they want to determine this via various standardized benchmarking assessment platforms. 

Answer: NO ONE MEASURE SHOULD EVER BE USED TO MAKE HIGH STAKES DECISIONS – although I hasten to note I would nearly always include high-stakes assessments in the triangulation of evidence.  I am opposed to grade-level notions as they can lead to many distortions.  Imagine a Grade 5 class where there can be NO students working at Grade 5 levels – half could be working at Grade 6 and above and thus are held up in the growth by being demanded to work at Grade 5, and the other half could be working at Grade 1-2 level and if the Grad 5 teacher advances them 2-3 grades they would still be seen as failing them as they are yet to Grade 5 – and of course giving them Grade 5 level work will cement them as behind!  Sadly, few systems in the world have abolished grade level curricula.  New Zealand for example, uses Levels based – with levels from 1-8 curricula and teachers are asked to identify what level and advance at least one level for each 2 years – much more sensible.   Again, I would be asked what defensible standard-setting method is used and note most systems. The bottom line is I want evidence from test scores from class assessments, artifacts of student work, teacher judgment, student evaluation of progress.