Validity is more critical to measurement than reliability. Maybe the validity versus reliability is more context related. In certain situations, you might be more interested in having valid results, such as for a blood sugar (glucose) measurement. That measurement has to be valid otherwise you might under or over dose on insulin which could lead to bigger health issues. But if you are weighing yourself, does it really matter if it's valid as long as the results are reliable and I can tell, relatively speaking, whether I'm getting heavier or lighter? Please comment.
Validity measures the actual accurateness of the numbers of a test. Reliability measures consistency of a test. For example, if you are stepping on a scale, it matters more if the numbers on the scale are valid rather ...
Discussion of validity versus reliability and whether it's more important for a test to be reliable over valid.