Is An Exchange Effect Taking Place?

By Jim Prevor, Editor-in-Chief, Produce Business

One can only be pleased that this research indicates that, at least under some circumstances, giving away free produce manages to boost produce consumption. One can only be disappointed that it only does so by a quarter cup per day on the day the free produce is distributed. This study doesn’t go into cost/benefit analysis, but one suspects that it will be difficult to prove that a 1/4 cup increase in produce consumption on certain days really reduces health care costs sufficiently to justify the expenditure.

The study seems to have a significant flaw in its design. The key line is this:

The study collected information on student food intake using diary-assisted 24-hour recall interviews. In FFVP schools, the diary was completed on a day on which FFVP fruits and/or vegetables were offered to students, allowing us to estimate the impact of FFVP on intake on FFVP days.

The problem is, of course, that by limiting the study to days in which free fruits and vegetables are distributed, you open the possibility that what we are seeing is actually an exchange effect. Think of it this way: imagine that, mindful of your health, you decide to limit yourself to one Big Mac each week and, typically, you go to McDonald’s on Wednesday to eat it. The other six days of the week, you go to McDonald’s and eat a salad. Now imagine that McDonald’s announces a promotion: Free Big Macs on Tuesday.

Quite probably you would switch your Big Mac Day to Tuesday from Wednesday to take advantage of the promotion. Now if McDonald’s studies its Tuesday customers Ð “The day on which free Big Macs were offered” — one will think it had a successful promotion, i.e., the promotion increased consumption of Big Macs because it would observe that the customers such as our prototypical one, customers who used to buy a salad on Tuesday, now buy Big Macs.

But that would be a deceptive interpretation of the success of the promotion. In fact, the promotion did not increase Big Mac consumption at all. It just switched dates of consumption.

With the USDA’s study, by only looking at the actual date the free produce is distributed leaves open the possibility that the children’s annual produce consumption did not change at all or, for that matter, even went down.

We don’t know a lot about produce consumption and its motivators. If we give children free apples on Wednesday, this might serve as a sampling tool and get the children excited about apples. They might, therefore, eat more apples than had they never been given the free apples. It is, however, also possible that children have a kind of the natural set point for certain foods to avoid boredom. So if given their druthers, the children might enjoy oranges three times a week if given some in school, but they may not eat one on Sunday.

One reasonable supposition might be that the nature of the free produce distributed might have a real impact on the overall effect. If the produce distributed is, for example, composed of novel items the students have not tried before — either new varieties of well-known items such as apples or completely new items — one might expect a greater long-term sampling effect. However, this might result in less short-term consumption as some children will reject the novel items.

Quality would quite probably have an impact as well. We would love to see some research on how students perceive the quality of what they are given. If the apples purchased are nice and crisp, and the schools maintain proper refrigeration, the sampling effect may promote produce consumption. If the apples purchased are low quality and/or the schools don’t maintain an optimal cold chain and the apples turn out to be mealy, the sampling effect may turn negative.

Another area we don’t know much about is the impact of free food distribution in school on parental purchases. If you know that your child gets free apples every day, does that make a budget-stressed parent buy more apples or buy fewer? Indeed, especially if one thinks of produce purchases for children as being motivated by parents’ desire to see their children eat healthy Ð might not the knowledge that the children are getting their “medicine” in school lead parents to shift spending to other foods? Maybe to other items in general? The thought might be the school is now providing the produce so we can spend the family budget on meat or shoes.

What about during school breaks? Does the distribution of free produce in school create fans for produce or does it create a mental association with a burdensome environment and lead children to want to avoid the product during summer vacation?

We just don’t know. This is all speculation, but it is reasonable speculation and it is not addressed at all by this research. The key question, quite obviously, is not whether on the days we give away fresh produce does produce consumption increase. The key question is: If we follow a free produce distribution of X frequency in the schools, what is the impact on children’s annual produce consumption?

This is a fairly obvious point, and the fact that the study was designed as it was makes one suspect that the bureaucrats chose a study design that would tend to support their initiative rather than give us valuable information on the impact of free distribution of produce on children’s produce consumption.