Abstract: Family support for older parents is often treated as an aggregate transfer from children to parents, although financial support and housework assistance are distributed among siblings within multi-child families. Using the 2014, 2016, 2018, 2020, and 2023 waves of the China Longitudinal Aging Social Survey (CLASS), this study matches respondents aged 60 or older with their two to five living adult children, yielding 39850 family-year observations and 114023 parent-child-year records. It distinguishes participation breadth, within-family share evenness, primary-provider separation, and share differences between financial support and housework assistance. A support-sharing index combines the proportion of participating adult children with a number-of-children-adjusted measure of within-family share evenness. The index describes observed behavioral distributions rather than normative obligations, negotiation, cooperation, or perceived fairness.

The results show that participation broadens and support-score shares become more dispersed for both forms of support. From 2014 to 2023, the support-sharing index for financial support rises from 0.757 to 0.884, while the corresponding index for housework assistance increases from 0.520 to 0.703. After adjustment for family characteristics, the differences between 2023 and 2014 in both component indices and the overall index are positive in families with two, three, four, and five adult children, although they are smaller in five-child families. Family-level total scores for both forms of support show no sustained decline. The findings remain robust to a 500-yuan participation threshold for financial support, alternative score assignments, individual fixed-effects models based on five waves linked through verified respondent identities, and fractional logit models. Estimates within each fixed child-number group provide the most direct evidence against a purely mechanical denominator effect. Hence, declining numbers of adult children alone therefore do not account for the observed aggregate trend.

Financial support consistently shows a higher level of sharing than housework assistance, consistent with the greater divisibility, additivity, and transferability of money and goods across distance. Unadjusted primary-provider separation fluctuates across survey years. The within-family distributions of support shares across siblings become more similar, whereas the unadjusted proportion of families with no overlap between primary providers of the two support types increases by about 1.4 percentage points between 2014 and 2023. After adjustment for family characteristics, however, primary-provider separation increases significantly by 7.2 percentage points between 2014 and 2023.

Within families containing at least one son and one daughter, son-daughter differences vary significantly across survey years in both financial support and housework assistance. In all eligible families, birth-order differences also vary significantly across survey years in both support types. These patterns are nonmonotonic: neither gender differences nor birth-order differences consistently widen or narrow over time. The findings describe observed behavioral distributions. The survey cannot determine whether broader participation and more dispersed shares arise from negotiated coordination, parental mobilization, low-intensity participation, or changes in individual contributions. Policy interventions should identify actual primary support providers and address time-intensive tasks rather than assign responsibility on the basis of gender or birth order. Future research should combine sibling-level longitudinal data with measures of negotiation, fairness, personal care, support quality, and caregiver burden.

Keywords: Multi-child Families, Family Support for Older Parents, Support Sharing, Gender Differences, Birth-order Differences

摘要： 本文基于2014~2023年5期中国老年社会追踪调查(CLASS)数据，将60岁及以上老年受访者与其健在成年子女配对，从参与广度、份额均衡性、主责分离和份额差异4个方面考察多子女家庭经济支持与家务协助的时期变化，并比较同一家庭内子女的性别与排行差异。研究发现，两类支持的参与范围总体扩大，支持份额趋于分散。控制老年人特征、家庭结构和居住安排后，两类支持分担指数及总体指数均显著提高。在特定数量健在成年子女家庭中的估计结果与多项稳健性检验表明，子女数减少不能单独解释这一趋势。经济支持分担水平始终高于家务协助分担水平，两类支持的份额分布趋于接近，主责分离原始比例仅小幅波动。在混合性别家庭中，两类支持的性别差异均具有时期异质性；在全部多子女家庭中，两类支持的排行差异也均具有时期异质性。性别和排行差异均未持续扩大或缩小。

关键词: 多子女家庭, 家庭养老, 支持分担, 性别差异, 排行差异