Daily Case Counts Are Not Meaningful

In Part 2 of my posts on COVID-19 in Ontario, I said that for Part 3 we’d be taking a look at the updated case statuses, as well as hospitalizations. However, I’d like to put that on hold for a moment to instead address something which I think needs be far more, and worryingly continues to occur.

I will also preface this post with the same caveats and disclaimer for my other analyses on this topic related to health and disease:

  • I am not an epidemiologist, nor am I a subject matter expert on disease nor public health policy
  • All handling of the data / code / statistics, interpretations thereof, and thoughts expressed are my own and only my own
  • This post may contain errors or omissions given the above which are only my own

I intentionally choose a rather inflammatory title for this post because I wanted to make this point strongly and because I feel it needs to be made, and strongly. As opposed to my usual writing style, I will not have an introduction and background, but instead state the bottom line up front:

Looking at daily case counts for COVID-19 alone is, at best, uninformed and naïve, and at worst, highly misleading. 

In fact, I will illustrate that:

  • Apparent exponential growth in positive cases could be explained by the growth in testing a population with a set amount of disease present
  • What might appear to be large daily changes in the absolute number of cases can be duplicated as nothing more than statistical noise due to sampling

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