First principle: A computer can free professionals from tedious, repetitive work which does not require judgment. It can provide facts and figures with lightning speed, giving domain experts more time to exercise their judgment thoughtfully [source].
Reality: HIT commonly makes work more tedious for clinicians, and there seems to be a not-so-subtle view in the industry that HIT can -- and should -- replace or oversee their judgment, and that clinicians are luddites for not embracing the "platform opportunities."
First principle: Clinicians need sysems built upon user-centric design principles (PDF) that provide cognitive support (per the 2009 National Research Commission report on HIT), not inventory systems of medical data.
Reality: the designer-centric Management Information Systems paradigms of the IT industry are widely used in HIT and are inappropriate in medicine with its "unbounded, poorly defined environment" of constant clinician improvisation that makes it appear to function smoothly (per a short article focusing on first principles itself, Nemeth & Cook's "Hiding in plain sight: What Koppel et al. tell us about healthcare IT", PDF).
First principle: modern medicine is a field unarguably and unalterably having science at it roots, and the approach to tools used within it must itself be based on science.
Reality: the HIT industry largely ignores science in favor of premature proclamations of "Mission Accomplished", in the form of self-exalting claims made without or with very little supporting evidence (a.k.a. 'puffery'), while studies that should be taken as a red flag about HIT (e.g., those highlighted at "2009 a pivotal year in HIT" languish in obscurity.
These principles are largely common sense, but sense, unfortunately, seems all too uncommon in healthcare in 2010.