From an article about the plague on the Channel 4 History website:
‘Being exact about the size of the population and mortality (deaths) so long ago is fraught with problems. Although there was a national system of registration of births, marriages and deaths, some families - for reasons of religious dissent or moral conscience - avoided the process.’
This historian evidently knows something the rest of us don’t!
Even the greatest expert can get it wrong sometimes. But this is a fairly fundamental misunderstanding (or at best a very poor explanation) on the part of someone who has an interest in population history.
As every family historian knows, there was no national system of registration in England before 1837. There was parochial registration. Each of the nine or ten thousand parishes of England kept records individually. They did not record births, marriages and deaths; they registered baptisms, marriages and burials.
The lack of a national system of registration is precisely why reconstructing the population of England in the past is ‘fraught with problems’!