&gt; Any exploration of data from negative-results experiments needs to be taken very narrowly, with a deep understanding of exactly what effect is being examined.<p>I disagree.  There&#x27;s value in data mining previous experiments, just not conclusive value.  As long as the results of such data mining are limited to generating new hypotheses (which are then tested by experiments explicitly designed to do so), I think this methodology can have great value.  In this particular case, I don&#x27;t think it&#x27;s a surprise that perioperative hypertension is associated with worse outcomes, but the hypothesis that controlling BP with medication before surgery and on through recovery might produce better outcomes is worth investigating.