Could student-run social media groups reduce university student dropout?

Universities are quite focused on student retention, and as I noted in this 2018 post, if we can identify at-risk students, perhaps we can help to find ways to ensure they succeed. However, around that time I had a summer research scholarship student looking into the reasons that students drop out, and it turned out that each student dropped out for quite different, and difficult to predict, reasons. I call this the Anna Karenina principle of dropout: 'all students who persist are alike; each student who drops out does so in their own way'.

What if there were a simpler way of reducing student dropout, that did not require universities to identify at-risk students in advance, but instead reduced the risk of dropout from the outset? That would seem to be an attractive proposition.

So, I was interested to read this 2021 article by Lucio Masserini (University of Pisa) and Matilde Bini (European University of Rome), published in the journal Socio-Economic Planning Sciences (ungated version here), which evaluates the impact of student-created social media groups, such as Facebook pages, on student dropout. Masserini and Bini use survey data from 1879 first-year students from a major university in Central Italy.

Why would joining social media groups reduce dropout? Masserini and Bini suggest that these groups may help students form social connections and feel greater 'belonging' within the university community, while also providing a way for students to share information about courses, assessments, and study materials.

The key challenge in the analysis is that students are not randomly assigned to join social media groups - they choose whether or not to do so. And students who join these groups may differ from those who don't in ways that would bias a simple comparison of the students who joined social media groups and those who didn't. For example, more engaged students, who are less likely to drop out, might also be more inclined to join university-related social media groups run by other students. Masserini and Bini deal with this using propensity score matching - which involves identifying 'control' students who didn't join a social media group but who are most similar to each 'treated' student who did join a social media group. Then, comparing their matched control and treated students deals with any observable differences between the students who did, and did not, join social media groups.

Masserini and Bini then report a range of results of the estimated impact of social media groups on dropout, based on different assumptions used to do the matching, and:

...with the exception of k=1 nearest-neighbour, all the estimates indicated that students joining groups or Facebook pages had, on average, a lower probability to dropout, compared with those who were not part of such groups. The results also showed that the extent of the difference between the treated and control groups was not negligible, as it varied from 0.081 to 0.113, depending on the matching algorithm.

So, the results suggest that joining student-run social media groups or Facebook pages reduces the probability of a student dropping out by between 8.1 and 11.3 percentage points. Now, I should note that I don't in general find propensity score matching to be terribly convincing as a way of dealing with selection bias. 

Now, I should note that I do not find propensity-score matching entirely convincing as a way of dealing with selection bias. Although matching can make the treatment and control groups similar on observed characteristics, there is still something that is different about the treated and control students that leads the treated students to choose to join social media groups and the control students to choose not to join. That something is an omitted variable in the propensity score matching approach, and it is unclear how big the omitted variable bias will be. If, for example, joiners are more motivated or feel more connected to university life, then some of the apparent effect of joining the group on the probability of dropping out may instead reflect those underlying differences. Masserini and Bini's results are robust across several matching methods and sensitivity checks, which is reassuring, but robustness checks cannot establish that there isn't some omitted variable bias in the matching.

Having said that, if we take these results at face value, then there may be some merit in having student-run social media groups that university students can join. We must bear in mind that these results come from a survey in 2016, and they may not have aged well. But social media groups still exist, and students still participate in them. It could be worth exploring whether these effects still hold, given that increasing student retention remains a key focus for universities.

Having said that, student-run social media groups would probably be a relatively inexpensive way for universities to reduce dropout. Now, these results come from students surveyed in 2016, and both social-media use and the university environment have changed considerably since then. Nevertheless, the basic idea remains plausible. Universities could support the creation of student-run groups and randomly encourage or 'nudge' some students to join, then compare their subsequent retention with that of students who were not encouraged. That experimental approach would provide more contemporary and causal evidence of whether the groups reduce dropout, rather than merely attracting students who were already less likely to drop out.

Read more:

• Predicting student success, and failure
• Big data, student dropouts, and failing fast

Egg prices will rise in New Zealand, even without a major avian flu outbreak

Last year, I posted about avian flu in the US and the impact on egg prices, noting that prices will rise. Thankfully there hasn't been a major outbreak of avian flu in New Zealand as yet, although it seems likely there will be soon. Domestic birds, such as chickens, are at risk, and as I noted in that earlier post, that affects the supply of eggs. And New Zealand egg suppliers are acting now, as the New Zealand Herald reported earlier this week:

It comes as New Zealand’s largest egg supplier Mainland Poultry, accounting for nearly 40% of the country’s eggs, is putting hundreds of thousands of free-range chickens into lockdown after the deadly bird flu virus was detected in the country last week.

Putting free-range chickens into lockdown will raise the costs of production for free-range eggs. The effect on the market for free-range eggs is shown in the diagram below. Before the chickens were locked down, the free-range egg market was in equilibrium, where demand D0 meets supply S0, with a price of P0 and a quantity of free-range eggs traded of Q0. The lockdown increases the costs of producing free-range eggs, which decreases supply to S1. This increases the equilibrium price of free-range eggs to P1, and reduces the quantity of free-range eggs traded to Q1.

Free-range eggs and colony eggs are substitutes. Once free-range eggs become relatively more expensive, some consumers will switch to colony eggs. The effect on the colony eggs market is shown in the diagram below. Before the change in the price of free-range eggs, the market for colony eggs was in equilibrium, where demand DA meets supply SA. The equilibrium price was PA, and the quantity of colony eggs traded was QA. Since some consumers switch to the relatively cheaper colony eggs, that increases the demand for colony eggs from DA to DB, increasing the equilibrium price of colony eggs from PA to PB, and increasing the quantity of colony eggs traded from QA to QB.

Overall, eggs are going to cost more, regardless of whether they are free-range eggs or colony eggs. And even without a major outbreak of avian flu. If avian flu does take hold in New Zealand, the price of eggs of both varieties will go up even further.

This week in research #136

Here's what caught my eye in research over the past week:

• Baker et al. (with ungated earlier version here) find that following legalisation, sports betting does not displace other gambling or consumption but significantly reduces savings, as risky bets crowd out positive expected value investments, and that these effects are concentrated among frequent bettors and low-savings households
• Alfani (open access) summarises the state of research on social mobility and income inequality in preindustrial societies, and identifies several promising avenues for new research
• Bostwick and Nguyen (with ungated earlier version here) find that when a student enrols in a triweekly (rather than biweekly) university class, they earn lower grades and are less likely to take a subsequent course in that same field
• Kaffine and Rao (with ungated earlier version here) find that the observed distribution of satellite orbits is well explained by profit-maximising satellite operator behaviour, and that collision risk plays a key deterrent role
• Yang et al. (open access) find that having daughters slightly increases the preference for gender equality and homosexual rights, using data across 39 countries from the European Social Survey
• Di Tella, Gàlvez, and Schargrodsky (with ungated earlier version here) find, using a laboratory experiment, that two strategies often proposed to reduce political polarisation on social media, removing access to the platform and exposing users to counter-attitudinal content, do not reduce polarisation and may instead produce mild increases
• Perroni et al. (open access) find, using a sample of 40,000 job vacancies in Vietnam, that physically attractive women are offered higher salaries, whereas physically attractive men are not
• Sentana and Gómez-Bengoechea comparing the behaviour of a groups of professional soccer players and inexperienced college students when they play the same two-person zero-sum game in both a soccer stadium (the field) and a video game (the lab), and find that while both groups behave consistently with the implications of mixed strategy equilibrium in the field, their behaviour rejects the theory in the lab

Are men's and women's soccer complements or substitutes?

Both my ECONS101 and ECONS102 classes touched on the subject of complementary and substitute goods this week (in different model contexts). Two goods are complements if consumers tend to consume them together. In that case, a decrease in the price of one good would increase the quantity that the consumer buys of both goods. Two goods are substitutes if consumers tend to consume one or the other. In that case, a decrease in the price of one good would increase the quantity that the consumer buys of the now-cheaper good, but decrease the quantity that the consumer buys of the other good (which is now relatively more expensive).

Often, it is easy to tell if goods are complements or substitutes. However, sometimes it is not straightforward. Consider the example of men's and women's soccer matches. Are they complements, or substitutes? If, when faced with the choice of whether to attend a men's or a women's soccer match, or both, fans tend to choose one or the other (and not both), then the matches are substitutes. On the other hand, if fans tend to go to both, then the matches are complements. Another way of thinking about this is that, when the price of one of the matches goes up, what happens to attendance at the other. So, if the ticket price for a men's soccer match increases and attendance at women's matches goes up, then they are substitutes, whereas if attendance at women's matches goes down, then they are complements.

Ultimately, whether men's and women's soccer are substitutes or complements is an empirical question. Fortunately, this 2025 article by Galila Nasser and Christian Deutscher (both Bielefeld University), published in the Journal of Sports Economics (open access), provides us with an answer. Or rather, they provide us with an answer in one particular context, which is German soccer.

Specifically, Nasser and Deutscher use data from the 2009/10 to 2018/19 seasons of the Frauen-Bundesliga, and look at the impact on match attendance when a Frauen-Bundesliga match is played on the same day as a men's Bundesliga match. They also consider whether the effect is larger when the overlapping men’s and women’s matches involve teams belonging to the same club. Their dataset contains 1,256 Frauen-Bundesliga matches, including 851 played on the same day as a men's Bundesliga match and 118 played on the same day as a match involving the men's team of the same club.

Controlling for the day of the week, week of the season, the weather, whether a UEFA Champions League match was also being played that day, and a variety of variables capturing the popularity of the match, Nasser and Deutscher find that there is:

...an approximately 15 percentage points decrease in attendance when women’s games coincide with men’s games on the same day.

A minor quibble with the paper is that when they say a 15 percentage points decrease, they really mean a 15 percent decrease. And the effect for matches played by the same club on the same day is somewhat larger, with attendance lower by about 16 percent. So, these results are consistent with men's and women's top-league soccer matches in Germany being substitutes (fans tend to go to men's or women's games, and not both). However, we can't conclude this for certain as the results are based on observational data so they are correlations, not causal. Nevertheless, Nasser and Deutscher conclude that:

For matches on the weekend, it is essential for clubs that have both men’s and women’s soccer teams in the first Bundesliga to avoid scheduling their matches on the same day.

Given that the seasons overlap substantially, and clubs in both leagues understandably want weekend matches, another option might be to make joint attendance at both men's and women's matches more attractive. Clubs with both men’s and women’s teams could offer a combined ticket covering matches played on different days, or even arrange occasional double-headers. As I note in my ECONS101 class, this sort of bundling can be an effective pricing strategy when there is heterogeneous demand across multiple products. Provided the variation in fans' willingness to pay for the ticket to the combined event is lower than the variation in fans' willingness to pay for the tickets separately, then bundling has the potential to increase total revenue overall. And that higher total revenue can then be shared between the men's and women's teams. Whether that would work here is another empirical question. Perhaps Bundesliga clubs could indulge us by running the experiment?