Testing in progress

Did the UK government hit its ‘100,000 tests per day’ target?

On 1st May, Health Secretary Matt Hancock MP claimed:

The number of tests yesterday — on the last day of April — was 122,347.

The target was 100,000 COVID-19 tests per day. ‘Tests’ includes testing kits sent out to homes and satellite centres. Even under this measure, the government failed to hit this target in later days.

Test, test, test

The UK government sought to increase its COVID-19 testing capacity.

Pledges used several wordings, differing in meaningful ways. On 2nd April through social media, the Office of the Prime Minister stated:

We will test 100,000 people per day by the end of the month.

Broadcasters and other news organisations reported the government met its target.

On the same day, a Department of Health and Social Care press release said:

The UK will carry out 100,000 tests for coronavirus every day by the end of this month, Health Secretary Matt Hancock pledged today.

Some people will have more than one test for clinical reasons. This is not the same target.

Counting in, counting out

There are multiple parts to the government’s testing programme.

For tests in the central programme, the department counts at the point of processing. For tests going outside that programme, the count happens when the test leaves.

DHSC counts home-testing kits when posted, not scientists when process those tests. Their notes reiterate tests are not counted twice.

This methodological choice poses several problems:

  • Validity: the measure was the number of tests done, rather than posted.
  • Overstatement: some people may not return home-testing kits, or be void.
  • Capacity: daily ‘tests’ might exceed the highest number we could process.

On 30th April, ‘delivery routes’ accounted for 40,369 tests. There were around 82,000 processed tests outside the delivery routes.

If we counted all tests at their time of processing, it is unclear if the tests for 30th April would be over 100,000. This is due to lag between sending out tests and processing.

The notes show that the test counts splits into (i) processed tests and (ii) posted tests. (Image: GOV.UK)

On the chosen measure, the government did not meet its target in later days.

The government also counts tests done for research purposes. These tests have support from the Office for National Statistics, universities, and others. Yet, the people in this testing pillar are not part of the ‘people tested’ figure.

Sir David Norgrove (Chair, UK Statistics Authority) has written to the Health Secretary. The letter requests greater clarity over testing targets.

How we define, measure and report statistics matters. During this pandemic, trustworthiness in accessible data with clear reporting is vital. Government departments need to show honesty and transparency.

This blog looks at the use of statistics in Britain and beyond. It is written by RSS Statistical Ambassador and Chartered Statistician @anthonybmasters.

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