Research

The Determinants of Sibling Similarity in Risky Behavior: Evidence from South Korea
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Scheduled presentations: SEA 2025

Abstract:
Sibling similarity in adolescent risky behaviors is well established, yet its underlying sources remain unclear. This paper provides the first empirical evidence from South Korea that this similarity cannot be fully explained by parental socioeconomic status or direct sibling spillovers, and that unobserved common factors, such as parenting style and household norms, also play an essential role in shaping it. Using four complementary identification strategies, I find that socioeconomic background accounts for part of the observed correlation but can sometimes suppress the mechanisms that generate it. The influence of older siblings is modest, largely contemporaneous, and can discourage rather than imitate certain behaviors. A substantial portion instead reflects these unobserved common factors, notably, 67 percent for drinking and 86 percent for violence, which are more readily shaped by parental conduct and household norms. These effects are most pronounced among brother pairs and siblings close in age. This finding underscores that sibling similarity in risky behaviors is structured less by peer imitation than by family norms and intra-household dynamics.

Birth Order, Gender and Parental Investments in South Korea
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Presentations: MEA 2025, PAA 2025, WEAI 2025, and SOLE 2025

Abstract:
The mechanisms underlying the impact of birth order on parental inputs and child outcomes are still unclear. This study considers that pregnancy planning, gender preference, and expectations can vary with birth order, affecting parental inputs. Using this perspective, I investigate the influence of birth order on parental inputs and children’s time use in South Korea. Apart from parental supervision, I find that parents are more involved in school activities and invest more in private education expenditures for first-born children than their later-born siblings. These results indirectly affect children’s time use, so that firstborn children spend more time in private education and less time in leisure activities than their siblings. Another key finding is that there is no gender effect in parental inputs, which provides evidence that the historically strong preference for sons in South Korea has considerably declined in recent years. These results support existing research on long-term outcomes associated with birth order and contribute to understanding parental investment behavior. The evidence consistently points to parents investing more in their firstborns in South Korea. This firstborn advantage has also existed in the country’s past, but the findings suggest that it may have intensified under sustained low fertility. As family size decreases, parents increasingly concentrate their limited resources on the eldest child to maximize educational and economic returns and enhance the household’s overall prospects.

The Effect of Maternal Employment on Children’s Time Use: Evidence from South Korea

The Influence of Household Income on Children’s Health in South Korea