Why do so many Chinese couples choose to give birth in the year of the Dragon? One straightforward explanation is the influence of superstitious beliefs.
Even couples who do not fully buy into Chinese zodiac mythology may still prefer Dragon babies because it feels auspicious and may somehow bring luck to the child or family.
Non-superstitious people may also be influenced by these beliefs. Fertility decisions can be influenced by peer behaviour and attitudes. Just hearing that their siblings, cousins, friends or neighbours are pregnant or planning to have a baby can inspire couples to do the same.
People may also give credence to collective wisdom, similar to the herd behaviour exhibited by speculators during the dotcom and other financial bubbles. If something was a bad idea, there wouldn't be so many people doing it, right?
Whatever the causes may be, the Chinese preference for giving birth in the year of the Dragon can have important demographic and macroeconomic consequences.
Previous studies from the US and Europe suggest that baby boomers people born between the mid-1940s to mid-1960s during an era of high fertility rates have lower lifetime earnings and may be more prone to criminal behaviour and suicide.
One key explanation for these negative outcomes is that there is more competition for resources, from teachers' attention to scholarships and jobs. Hence, this is a case where following the herd may not be the wisest course of action.
TRAGEDY OF LARGER COHORTS
Our research finds strong evidence that Chinese men and women born in the year of the Dragon are less likely to be admitted to local universities.
When we delved further into the data, we found that the effects are largely due to lower admission scores, rather than differences in application ratios or university policies.
In fact, we found that the education system anticipates and actively seeks to reduce the impact of large cohorts by increasing school resources and enrolment to ensure that all cohorts have access to good education.
Nevertheless, despite these efforts, we document lower academic preparation among Chinese Dragons prior to university entry.
Consistent with this result, we find that they also have significantly lower earnings by around 6 per cent, are more likely to be self-employed and less likely to be in formal employment.
Thankfully, the effects appear to dissipate among older Dragon cohorts, suggesting that the decline in earnings is due to the inability of the market to absorb a sudden surge in supply of graduates and work seekers when they first enter the labour market.
NEGATIVE EXTERNALITIES ON REST OF SOCIETY
One of the most intriguing findings in our research is that the macroeconomic effects are not limited to Chinese Dragons only.
Non-Chinese Singaporeans born in the year of the Dragon also tend to experience a lower probability of admission into local universities and lower earnings, although the effects are weaker than that for the Chinese themselves.
Interestingly, another group affected by the Dragon year phenomenon are Horse babies. The number of babies born in the year of the Horse is not especially large (the year of the Dragon is the only year which exhibits statistically significant increases in birth numbers).
However, due to National Service requirements, Dragon men go to universities or start their jobs with female counterparts who are two years younger women born in the year of the Horse.
Our analysis shows that, as expected, Chinese women born in the year of the Horse have significant lower earnings than those born in other cohorts. By contrast, men born in the same year are not affected, even though both groups have similar levels of academic preparation prior to university and similar chances of admission to local universities.
The above finding is especially useful because it strongly suggests that at least part of these negative macroeconomic effects must be due to the size of the cohort itself.
If the Dragon phenomenon were due to increases of fertility among lower income Chinese families, then we may suspect that family background is the main explanatory factor behind why Dragon cohorts tend to have lower earnings.
However, the results for Horse babies do not support this hypothesis. If family background is the driving force behind our results, we would expect no effects on earnings since there is no evidence of fertility selection for these cohorts.
The only explanation for the unusually low level of earnings for the women is that they are matched with a large cohort (while the men are matched with a normal-sized cohort of women, born in the year of the Monkey).
DEVIATING FROM HERD MENTALITY
The evidence suggests that Chinese couples shouldn't aim to give birth in the year of the Dragon. The broader moral of the lesson, however, points to the power that non-scientific personal beliefs continue to have on our fertility and other behaviours.
Young couples today appear to be less susceptible to superstitious beliefs, with evidence that the Dragon year effect has become less pronounced in more recent cohorts.
However, a growing pool of evidence from other developed countries finds that a large proportion of the population subscribes to fertility myths. In particular, both men and women tend to overestimate the ability of advancements in medical technologies such as in vitro fertilisation to overcome the detrimental effects of age on couples' ability to have children.
These fertility myths are fed in part by peer behaviour and attitudes, as the average age of childbearing has risen over time.
In addition, the media routinely highlights older female celebrities who achieve motherhood, while less successful cases are ignored. While these stories send a positive and reassuring message, especially to working women, they also contribute to creating a form of collective wisdom that does not align fully with scientific evidence.
As with the Dragon year phenomenon, couples can avoid unintended consequences by deviating from the herd mentality and making informed fertility decisions based on their own preferences and constraints.
This piece was first published in Channel NewsAsia on 10 February 2018.