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Pertinent Negatives, as Applied to Software

EMTs and Paramedics On-Scene

At one point in my life, I was a volunteer Firefighter/EMT. During my time working in paramedicine, I learned a valuable concept: the pertinent negative.

Let’s say you’re examining someone who fell from a height. In your report you node that yes, they had a laceration on their hand. But it is also important to note that you examined them and found no evidence of any other broken limbs. Not noting your investigation into broken limbs could mean one of two things: either you didn’t check their limbs, or you did and found nothing of concern.

By noting the pertinent negative, you clear up that ambiguity.

I find this concept incredibly useful in software. Frequently, I need a pertinent negative to do my job well. (Did that script complete without errors, or did it not even run? In a report, a 0 entry tells me that the item did fit my search criteria and it had no requests. Etc.)

I have to say that this concept of pertinent negatives keenly reminds me of how important an ‘invention’ zero was.

[youtube http://www.youtube.com/watch?v=Nvc2PPTlW7k]