Labour leader Kier Starmer scored a small victory over Prime Minister Boris Johnson at prime minister’s questions (PMQs) this lunch time.
Starmer confronted the PM with the idea that only a third of those infected with Covid in the UK are being followed up in the government’s new test and trace system. Cue comments such as “forensic”, cheers all round and a nice clip for Twitter.
Starmer’s statistics were sound, individually. He ostentatiously waved copies of government slides to make his point. The combination of the statistics was misleading though. One was an Office of National Statistics estimate of the prevalence of Covid in the poplulation based on random testing. The ONS tested 24,413 people to find just 10 cases. From this data the ONS extrapolate to make a population estimate of 33,000. The other was the number of people contacted by the government’s test and trace system, 10,192 people, only one third of those affected apparently.
Johnson himself accused Starmer of being misleading and was upbraided by the speaker.
But, Starmer was misleading in the way he combined these statistics. The ONS estimate of 33,000 includes a majority of people who will be asymptomatic. We could in theory find these people if we tested the entire population every week say but this is way, way beyond what any country can do now.
Johnson got half way to rebutting this attack. He pointed out that the ONS number was an estimate. He failed though to explain the trick that Starmer was pulling.
Starmer’s apples and oranges comparison was not made in the heat of the moment. This was a well prepared question backed up with the slides he theatrically waved in the chamber. This line must have been tested in rehearsal for PMQs. He knew what he was doing. This was a cynical ploy. His argument rests on a lie. It was prepared in advance. The elision of two different statistics was misleading.