At the time of writing there are currently 161 cases of Covid-19 per 100,000 in my area, according to a page on the BBC website. That’s the same as 0.161% of the population.
Which statistic sounds more daunting?
Daniel Kahneman writes in Thinking, Fast and Slow that when formatting a probability, a frequency (e.g. 161 per 100,000) elicits a more emotional response than a percentage does. We picture 161 people that are infected, and therefore realize that there’s a threat. It’s much more difficult for us to imagine 0.161% as a threat, and formatting the statistic in this way makes it seem like Covid-19 is much less of an issue.
I believe that the UK government are familiar with this phenomenon, and have chosen to present statistics as total case numbers and frequencies per 100,000 of population (instead of percentages). Amid a national lockdown, the government of course wants compliance and this is a small detail that can influence the public perception of Covid-19.
I am not suggesting that the government have been deviant or unethical in any way, but the fact that the format in which statistics are written does influence the way that we think about things.