When conducting studies where mortality is an important outcome, let’s revisit how we go about answering the question “how many?”
The authors remind us that simply recognizing the limitations of our knowledge is a critical step. This leads us to their discussion on ultimately decreasing pig mortality.
Some of their logic may help us better understand our current situation with Covid-19. After all, swine veterinarians and academics have been dealing with diseases rampaging in swine populations for decades < link >.
Source: National Hog Farmer, September 10, 2020. Link. Just because we don’t (and may never) fully understand the true complexity behind why pigs die doesn’t mean we can’t generate approaches to reduce the impact on animal welfare and production.
Determining sample size for more complex outcomes such as mortality, which often does not have a bell-shaped curve, is much more complicated. Finding a numerical difference in tests with insufficient sample size can lead you to believe the intervention was successful and result in wasteful spending on false cures.
INSIGHTS: I never enjoyed the mathematics of statistics. I have also often wrestled with rules of thumb established from a seemingly small sample of people who respond to surveys applied to a full population. Tongue in cheek? Honestly, yes and no. Regardless, this article resonated with me . . . and not just on the topic of pigs.
I believe animal health pros remain in a unique position to lead during epidemics and pandemics. Why? Because we collectively have experiences proactively managing diseases. Our careers encompass prevention: one individual animal or location at a time or recovering from a prevention failure. It is what we do!