Since the inception of the Hospital-Acquired Condition Reduction Program (HACRP) in 2015, those of us involved in the world of hospital infection control have become used to looking at HAC scores. For a few years, these hospital scores have been expressed as a number between 1 and 10. Now, HAC scores look different: They can be positive or negative, and only seem to be between -3 and +3. What gives?