&gt; Less data is never the answer. Just my 2 cents.<p>That assume perfectly rational reactions.  Many people can&#x27;t deal with &quot;You tested positive for X.  We should keep an eye on it and see if it develops into something.&quot;  It makes them nervous.  They want a pill.  They want surgery.  etc.<p>The problem with even really good tests that test exactly what you want is that they have 4 modes-2 good: test positive for X&#x2F;you actually have X, test false for X&#x2F;you don&#x27;t have X and 2 bad: test positive for X&#x2F;you actually don&#x27;t have X and test negative for X&#x2F;you actually do have X.<p>The problem is that when the actual instance of &quot;you have X&quot; is very low, the &quot;test positive for X&#x2F;you actually don&#x27;t have X&quot; can swamp your signal.<p>Add in the natural noisiness of biological systems, and you wind up with lots of incorrect assessments.