61 reasons for the necessity

Britain in the last decade
wasn’t so much a lie
as a mistake.

When the Chancellor was giving
reasons for the necessity
of austerity
he relied heavily
on recent findings
by two Harvard economists.
They had
‘shown’
via a model built using
44 countries over
two centuries
that
when a government’s ratio of debt to GDP went over 90 per cent,
the economy shrank.
The Chancellor
drew directly on this research:
‘The latest research suggests
that once debt reaches
more than
about
90 per cent of GDP
the risk of a
large
negative
impact
on long-term growth becomes
highly significant.’
Cuts were planned.

A graduate student at Amherst College,
Thomas Herndon,
was set to check the Harvard numbers,
as a homework assignment.
He tried to replicate the findings
but couldn’t.
So he asked them for the original data,
which they (admirably)
sent.
Herndon checked the numbers
and found a mistake.
The economists
had intended to sum twenty
rows of data
but had only used fifteen.
When all twenty were included
countries with debt to GDP ratios over 90 per cent
were no longer shrinking.
But by this point
the government simply couldn’t back down.

[London Review of Books, 21/09/2023, ‘Get a rabbit’]