Quarterly provincial GDP estimates are not published in South Africa, but are available from private sector providers. In today’s post, we compare historical annual GDP growth rates for the Western Cape against implied figures from quarterly estimates from a private sector provider for which these estimates can be obtained from public domain reports. We take care to present the figures in a comparable form and show that there are meaningful differences in the private sector estimates published each year and subsequently published official statistics. Private sector providers will revise their historical estimates after official statistics are released, so these differences disappear if one compares historical ex-post (current vintage) estimates. This is why policy analysis must incorporate real-time estimates.
