Has the Census revealed 'record' population growth?

17 July 2012

The Financial Times and the Guardian both reported yesterday that "the population of England and Wales grew over the past decade at its fastest rate in 100 years."

Meanwhile the Independent and the BBC were among those to point out that the release of 2011 Census data had shown the largest population growth since records began over 200 years ago in 1801.

So has a 100- or 200-year record been broken with the release of the latest population estimates?

It isn't difficult to see where these claims come from, and the Office for National Statistics' (ONS) analysis of the Census results might seem to lend credence to the notion that the population growth had hit an all-time high:

"The population of England and Wales has grown by 3.7 million in the 10 years since the last census, rising from 52.4 million in 2001, an increase of 7.1 per cent. This was the largest growth in the population in England and Wales in any 10-year period since census taking began, in 1801."

But does that mean that the Guardian and FT are wrong?

What isn't immediately clear from the ONS's interpretation of the figures is whether it thinks the sheer increase in the number of England and Wales residents, at  3.7 million, is the largest on record or if it is the rate of increase, at 7.1 per cent, that has reached a new peak.

A quick look at the historical population data shows that the rate of growth actually exceeded 7.1 per cent every time it was measured in the first 100 years of the Census's existence.

(* Census data wasn't collected in 1941)

What the data does show is that the numerical jump in the population count of 3.7 million is larger than at any other point on record, dwarfing the rises typically seen in recent decades.

However historically-speaking, this is less remarkable, as a larger population base will naturally lead to larger jumps in the number of residents if the birth rate remains constant. Hence every Census bar one until the First World War saw a 'record' increase in population.

As the graph above shows, the rate of population growth has actually slowed consistently ever since it was first measured, although the rate of increase in 2011 is the highest it has been for a century.

Neither the Independent and BBC, nor the Guardian and FT, have got their figures wrong. The population growth over the past decade can either be the sharpest in 100 or 200 years depending upon whether you consider the rate of increase in the population or the sheer number of additional people that live in the country.

Ironically, the only report that seems a little confused is the one published by the ONS, where this distinction is only clear after a careful reading.

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