Read on Twitter
Something strange is going on with the positivity data and I'm not sure what to make of it.
Might be of important for anyone who's following the data.
Perhaps you have a better idea about what's going on than me
@chrischirp @jburnmurdoch @COVID19actuary @RP131 @fascinatorfun
Might be of important for anyone who's following the data.
Perhaps you have a better idea about what's going on than me
@chrischirp @jburnmurdoch @COVID19actuary @RP131 @fascinatorfun
Case numbers appear to be coming down quickly (almost linearly over the last few weeks - UK).
Nothing too unusual in that, although it's always good to check the positivity rates in case this is caused by a decrease in testing.
Turns out testing hasn't decreased much recently.
Nothing too unusual in that, although it's always good to check the positivity rates in case this is caused by a decrease in testing.
Turns out testing hasn't decreased much recently.
Looking at English regional positivity rates on the COVID dashboard:
https://coronavirus.data.gov.uk/
Paints a positive picture of decline in almost all regions (with the exception of the North West).
https://coronavirus.data.gov.uk/
Paints a positive picture of decline in almost all regions (with the exception of the North West).
The first big discrepancy comes from looking at the positivity data from PHE ( https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/956709/Weekly_Flu_and_COVID-19_report_w4_FINAL.PDF) we see a steeper decline in all of the regions in comparison to the dashboard data.
This is perhaps even clearer when we look across the whole of England and compare the positivity rate data on the same graph.
PHE clearly shows positivity coming down faster.
PHE clearly shows positivity coming down faster.
Adding the ONS infection survey into the mix paints a different picture still.
Although these two "positivity rates" are not directly comparable, you would expect them to do something broadly similar all other things being equal...
https://www.ons.gov.uk/peoplepopulationandcommunity/healthandsocialcare/conditionsanddiseases/bulletins/coronaviruscovid19infectionsurveypilot/29january2021
Although these two "positivity rates" are not directly comparable, you would expect them to do something broadly similar all other things being equal...
https://www.ons.gov.uk/peoplepopulationandcommunity/healthandsocialcare/conditionsanddiseases/bulletins/coronaviruscovid19infectionsurveypilot/29january2021
But ONS has shown relatively little change in positivity over the last week and even since the end of December the fall hasn't been huge (even in the raw data - forget the models).
REACT results released yesterday are now also starting to show a slightly steeper decline: https://spiral.imperial.ac.uk/bitstream/10044/1/85703/10/react1_r8_full_preprint_1.1.pdf
But none of these sources of data seem to paint a coherent picture.
But none of these sources of data seem to paint a coherent picture.
Understanding how cases are changing is clearly important for assessing the impact of this lockdown and will inform how we start to release restrictions.
I don't know what to make of it all. So the question I am asking is, what the hell is going on?
Any insights much appreciated.
I don't know what to make of it all. So the question I am asking is, what the hell is going on?
Any insights much appreciated.
Thanks to Bob Hawkins for preparing the dashboard and PHE positivity comparisons.
