So, why are covid death rates higher in some states?

A common hypothesis is that there’s a strong correlation between death rates and the percentage of a state’s population that that is vaccinated.

The hypothesis seems reasonable, so I decided to to test it…


Below is a scatter chart of the 50 states … on the horizontal axis is the current vaccination rate (% of residents 18 and over who have received at least 1 shot) on the vertical axis is the past month’s covid death rate (deaths per million residents).


To the naked eye, the chart is more buckshot than correlation.

Arguably, there’s a slight positive relationship … with emphasis on “slight” since the R-squared is a mere .0325 … which is, for all practical purposes, not statistically different from zero.

Let’s dig a little deeper…


Below is a matrix that puts names names on the above dots.

The rows are vaccination rates — over 60% at the top (good), under 40% at the bottom (bad).

The columns are the  past month’s covid death rates — left is under 40 deaths per million (good), right is over 0 deaths per million (bad).

So, for example, the states in the blue quadrant have high vaccination rates and low death rates.

The states in the red quadrant have low vaccination rates and high death rates.

Those are to be expected.

But, there are a lot of states in the orange (high death rates despite high vax rates) and yellow quadrants (low death rates despite low vax rates)

click for a full-size, printable PDF


Let’s look at the top rows … the states that have vaccinated the highest percentages of their residents.


A couple of observations:

> Nearly all of the states in the top 2 rows (high vaccination rates) are Northern Blue  states … most with dense metro population centers.

> A majority of these high vaccination rate states still have high death rates … and, in aggregate, these states account for a disproportionate share of current covid deaths.

See Nums: 10 states account for 2/3′;s of covid deaths

> Most of the current high death rate states have had high death rates from the get-go … vaccinations  may have cut the death rate from previously high levels, but the states are still challenged.

> Two states — Massachusetts & California — have currently low death rates substantially below their pre-vax levels … likely attributable to vaccinations, but there may be other factors in play.


What about the bottom rows – the low vaccination rate states?


> Generally, states with low vax rates are Red states with dispersed populations … more rural … with many in sunnier Southern climates.

> Michigan and Wisconsin are outliers to the general rule … Michigan is particularly interesting since it has been one of the most locked down, masked states … yet, the state has a relatively low vax rate (which their wacky gov has laid off against supply constraints) … and still has a sky high death rate.


Bottom line: Covid death rates are a lot more complicated than simply tying them to vaccination rates.

Are the most vulnerable being vaccinated? What other factors are in play?

We’ll keep thinking about it … your thoughts?

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