May 22nd, 2011 by Hafiz Noor Shams
Does the rounding mechanism in Malaysia contribute to inflation?
Malaysia implemented the rounding mechanism in 2008. All prices are now rounded to the nearest five sen. The mechanism makes the one sen coins redundant although the coins themselves are legal tenders still.
To answer the question, I have an anecdote to tell.
Australia also employs the rounding mechanism. The only difference between the Australian and Malaysian systems is that the Down Under version applies to cash transactions only. In Malaysia, prices are rounded regardless of transaction types.
I am a stingy person. In the case with the Australian system, I was literally penny wise, pound foolish. Well, more penny wise and less pound foolish. Considerably less for the latter.
Anyway, whenever I went out shopping in Sydney, I would check up on the price and see if whether it would be rounded up or down. If rounded up, then I would use my card so that I would save a couple of pennies. If down, I would use cash to get penny discounts.
I did that because I thought these firms were getting too much of the good stuff. I also thought they might have purposely priced their items so that prices would always rounded up in their favor. Hey, if I were the shopkeepers, I would do that too. And some of these businesses are big. I am not anti-business or anything but I sure do think they can make do just fine by not squeezing another penny out of me. Not when I am still alive damnit!
So, I would do that. After awhile, I thought maybe, it did not matter in the end. The saving from this little exercise was really small that if the whole two years worth of saving were combined, I could probably get a candy. One candy. That would not have impressed the ex-girlfriend by much.
The point is that even if the rounding mechanism contributes to inflation, I doubt it is significant.
But that is an anecdote. Here is something more scientific.
Chande and Fisher in 2003 wrote about the effect of rounding mechanism in Canada. They concluded that the expected impact was small. In fact, the effect of rounding on inflation is expected to be zero. Why?
They assumed the last digit that matters in rounding is uniformly distributed from 0 to 9. Therefore, the probability of each digit occurring is 10%. Since four digits will be rounded up, four digits will be rounded down and another two do not need to be rounded, the expected extra cost or revenue incurred or earned from the mechanism is zero. In simpler terms, the mechanism’s expected contribution to inflation is zero. On average, the sellers and the purchasers do not enjoy or suffer extra revenue or cost due to the rounding mechanism.
The authors ran a simulation and concluded that for purchases more than two items, the last digit of the price did distribute uniformly across the natural number line.
For purchases of less than three items, the digits did not distribute evenly. This suggests that this kind of purchases does contribute to inflation but since it is one or two purchases, its impact is likely small as suspected by Chande and Fisher.
How about strategic pricing?
Let me quote the paper I mentioned:
Thus, in order to take advantage of rounding, a retailer would need to know how frequently different combinations of items are purchased. While retailers like Tim Horton’s would have access to such data, Table 2 suggests that even if prices were strategically adjusted by firms to squeeze extra revenue from their customers, the amount per transaction would be so trivially small as to have little impact on consumer behaviour or welfare. Moreover, we have focused on price-setting by a single firm and ignored the reaction of other firms selling in the same market. It is an open question whether an oligopolistic market would lead to equilibrium prices that exploited rounding to the detriment of consumers. Indeed, anecdotal evidence from New Zealand suggests that such fears maybe unwarranted. Correspondence with the Reserve Bank of New Zealand, which in 1990 removed its 1- and 2-cent coins from circulation, revealed that some supermarkets at the time advertised they would always round in favour of the customer. [Dinu Chande. Timothy C. G. Fisher. Have a Penny? Need a Penny? Eliminating the One-Cent Coin from Circulation. Canadian Public Policy. December 2003]
 — The Rounding Mechanism is a method whereby the total bill amount (including goods and services subject to tax) is rounded upwards or downwards to the nearest multiple of 5 sen. In this regard, total bill amount that ends in 1, 2, 6 and 7 sen will be rounded down while 3, 4, 8 and 9 sen will be rounded up to the nearest multiple of 5 sen. [Frequently Asked Questions on Rounding Mechanism. Bank Negara Malaysia. Accessed May 19 2011]