Z-scores are used to compare mortality pattern between different populations or between different time periods. The higher the Z- score the greater the difference between the expected number of deaths in a given period and the total number of deaths actually recorded.
The graphic shows that the UK as a whole has a higher number of excess deaths than any other European country and that England has a higher number of excess deaths than other nations in the UK.
How does this square with the relaxation of the lockdown in England?
I’m not saying that the lockdown shouldn’t be lifted – of course it should be lifted but Johnson said that he is going to be ‘led by the science’ and my criticism is that he doesn’t seem to be led by that. A science led response would question the particularities of conditions and responses that have caused England to be more strongly impacted than elsewhere. Decisions should be based on the answers to those questions and they should be implemented in a graduated way consistent with restarting the economy in a rational manner.
Johnson said that all workers who were unable to work from home should go back to work. This is impossible because it is quite obvious that people in sectors of the economy, such as hospitality, that are locked down will not be able to return. Perhaps Johnson meant construction and manufacturing, perhaps he meant other sectors too but what he said was ‘all workers who cannot work at home’. I’ve been listening to people trying to unpack what he meant all day. This is not good enough. The minimum that should be expected from a leader is clarity and that has been wholly absent.
Source of Graphic: https://www.euromomo.eu/graphs-and-maps/
“The higher the Z- score the greater the difference between the expected number of deaths in a given period and the total number of deaths actually recorded.”
The above statement is slightly misleading. The z-score is a measure of how unusual the number of deaths is compared to the past. It represents the probability that the current number of deaths can be explained solely by the variation seen in the past. A high z-score represents a low probability that the current number of deaths is due to the historically measured variation.
For example, imagine there are two countries with the same average number of deaths in the past but the second country had more variation over time. If both countries then experience the same increase in the number of deaths over the historical average number of deaths the second country will have a lower z-score than the first country.
“The graphic shows that the UK as a whole has a higher number of excess deaths than any other European country…”
It may be true that the UK has had a higher number of excess deaths than any other country but that graphic does not show that. It display z-scores not excess deaths. It does show that the number of deaths experienced in England during that week is less likely to be due to the natural variation seen in the past than it is for any other country.
Thank you for the clarification.