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The non-price effects of soda taxes and bans
The American Journal of Agricultural Economics just published a paper I co-authored with Sunjin Ahn, who is a post-doc at Mississippi State University entitled “Non‐Pecuniary Effects of Sugar‐Sweetened Beverage Policies.” (for the non-economists out there, “non-pecuniary” just means non-price).
Here was our motivation for the study:
We tackled this issue by conducting a series of experiments through surveys with consumers. We asked consumers to participate in a series of simulated grocery shopping exercises. Consumers first made choices between beverage options at a given set of prices, and then they were randomly allocated to different treatments where either:
A) prices of SSB increased but respondents were not told why,
B) prices of SSB increased and respondents were told it was a result of a soda tax,
C) prices of SSB increased and respondents were told it was a result of a shortage of sugar beets and sugar cane,
D) the size of SSB was reduced but respondents were not told why,
E) the size of SSB was reduced and respondents were told the reduction was due to a government ban on large sized sugared sodas, or
F) the size of of SSB was reduced and respondents were told the reduction was due to a plastic shortage.
By comparing how choices of SSBs change when people were told prices or size changes were a result of a policy vs. other non-policy factors, we can get a sense of the size and direction of the non-pecuniary effects.
When conducted our first study in 2016, we found significant results related to the SSB taxes. In particular, our results suggested people who were told price changes were a result of a tax were more likely to choose SSB than people who were not given a reason for the price change. We certainly weren’t the first to find such an effect. Here is a bit about previous research on this topic:
When we sent the paper off for review, we received a number of valuable comments, which caused us to make a number of changes to our experiment, and repeat the study with some extensions in 2019. What did we find with these newer data? On average: nothing, nada, zilch. There was no significant difference in the average market share of SSBs across the various information treatments. However, we did find significant variability in the treatment effects, meaning some people choose more SSBs when they knew it was a tax/ban and others chose less; however, these variations were only partly explained by demographic effects. In summary, our results didn’t provide a clear answer on the question we sought out to address: non-pecuniary effects, to the extent they exist, seem to work in different ways for different people, making the net effect small and hard to identify, at least in our experimental setting.
A note on the publication process is worthwhile. Normally, it is very hard to publish null results. This is problematic for the advancement of science because it results in publication biases like the file draw problem. To the credit of Tim Richards, the journal editor, and the three anonymous reviewers at the American Journal of Agricultural Economics, we received a positive reaction and ultimately, after a more changes, acceptance for publication even though we failed to replicate our previous result and found null effects. This is really an example of peer-review working at it’s best.
Unscrambling COVID-19 Food Supply Chains
That is the tile of a new paper with Trey Malone and Aleks Schaefer, both at Michigan State University. Here is the abstract:
We tried to tease out the effect of the pandemic itself on egg prices from the impact of FDA rules that barred eggs from easily moving from the restaurant to the grocery market. Here’s what we find on that latter point.
The key results as they related to impacts on commodity egg prices are shown in the following graphs (the dashed lines are our forecasts of what would have happened had COVID19 not occurred).
You can read the whole paper here.
Beef and Pork Marketing Margins and Price Spreads during COVID-19
That’s the title of a new working paper co-authored with Glynn Tonsor at Kansas State University and Lee Schulz at Iowa State University. As I’ve previously written, there has been a lot of interest in price movements of livestock relative to wholesale meat during the pandemic. Just last week, there was another call by the U.S. Congress for research into the issue. Recently, there have been several good discussions of this issue including a piece by Cortney Cowley with the Kansas City Federal Reserve Bank and a report by the USDA Agricultural Marketing Service.
Here is the abstract of our paper:
You can read the whole thing here.