Compounding wisdom from a surprising source

I really struggled when Health Minister Aaron Motsoaledi announced (many sources, but here is one) that private healthcare costs have increased by 121% over the last decade.

He continued: “Over the past decade, private hospital costs have increased by 121%, while over the same period, specialist costs have increased by 120%.”

Anyone who measures growth over long periods without using compound annual rates can’t be taken seriously. Abusing numbers for shock value is a sure sign of a weak argument or a lack of appreciation for long-term issues.

121% over nine years (2001 to 2009) equates to an average cumulative annual growth rate of 9.2%. Now medical price inflation of 9.2% is high given inflation over the period and modest real growth in GDP and salaries. But 9.2% tells a very different story to a layperson than 121%. The 9.2% is more useful, more comparable to inflation, more easily able to be understood. 121% is more shocking.

I was really encouraged to read this in a story, quoting Matlala from HASA:

He pointed out that while the green paper said private healthcare costs had increased 121% between 2001 and 2009, this should be contextualised against the backdrop of contributions to public healthcare increasing by more than 100% over the same period.

“Even the price of bread has increased 111% over the decade… We have to face up to the fact that the cost of living has gone up, including healthcare,” Matlala said.

Finally, someone quoted acknowledging that the 121% figure is utterly misleading.

Incidentally, 111% over 9 years is equivalent to an 8.7% annually compounded growth rate, just 0.6% per annum below healthcare cost increases. 


Published by David Kirk

The opinions expressed on this site are those of the author and other commenters and are not necessarily those of his employer or any other organisation. David Kirk runs Milliman’s actuarial consulting practice in Africa. He is an actuary and is the creator of New Business Margin on Revenue. He specialises in risk and capital management, regulatory change and insurance strategy . He also has extensive experience in embedded value reporting, insurance-related IFRS and share option valuation.

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