Table 4.
Estimated impacts of US workplace breastfeeding legislation on the proportion of children ever breastfed at 6 months.
| M1 | M2 | M3 | M4 | M5 | |
|---|---|---|---|---|---|
| DID policy lead 5–6 years | 0.002 (−0.011, 0.014) | ||||
| DID policy lead 3–4 years | −0.001 (−0.015, 0.012) | ||||
| DID policy lead 1–2 years | 0.012 (−0.002, 0.027) | ||||
| DID policy effect | 0.182*** (0.164, 0.200) | 0.023*** (0.011, 0.034) | 0.026*** (0.012, 0.040) | ||
| DID introduction year | 0.011 (−0.010, 0.031) | ||||
| DID policy lag 1–2 years | 0.020*** (0.004, 0.036) | ||||
| DID policy lag 3–4 years | 0.025*** (0.008, 0.042) | ||||
| DID policy lag 5 years onwards | 0.036*** (0.018, 0.053) | ||||
| DID strict enforceability | 0.016* (0.001, 0.031) | ||||
| DID weak enforceability | 0.031*** (0.014, 0.047) | ||||
| Average mother's age (years) | 0.001** (0.0003, 0.002) | 0.001** (0.0002, 0.002) | 0.001** (0.0002, 0.002) | 0.001** (0.0002, 0.002) | |
| Average number of children in household under 18 years old | 0.007 (−0.034, 0.049) | 0.007 (−0.034, 0.049) | 0.008 (−0.036, 0.050) | 0.007 (−0.035, 0.050) | |
| Average years of mother's education | −0.002 (−0.004, 0.0005) | −0.002 (−0.004, 0.001) | −0.002 (−0.004, 0.0004) | −0.002 (−0.004, 0.0004) | |
| Average health expenditures per capita | 0.014 (−0.005, 0.034) | 0.018* (−0.002, 0.037) | 0.016 (−0.003, 0.036) | 0.014 (−0.005, 0.034) | |
| Proportion of married mothers | −0.053 (−0.162, 0.056) | −0.051 (−0.160, 0.058) | −0.053 (−0.162, 0.055) | −0.055 (−0.165, 0.054) | |
| Proportion of White mothers | −0.275** (−0.542, −0.008) | −0.265* (−0.532, 0.001) | −0.262* (−0.529, 0.005) | −0.265* (−0.532, 0.002) | |
| Proportion of African-American mothers | −0.407*** (−0.697, −0.118) | −0.379** (−0.669, −0.088) | −0.399*** (−0.689, −0.110) | −0.400** (−0.690, −0.109) | |
| Proportion of Hispanic mothers | 0.057 (−0.267, 0.381) | 0.065 (−0.258, 0.389) | 0.057 (−0.267, 0.381) | 0.068 (−0.257, 0.393) | |
| Median household income | 0.002*** (0.001, 0.004) | 0.002*** (0.001, 0.004) | 0.002*** (0.001, 0.004) | 0.002*** (0.001, 0.003) | |
| Unemployment rate | −0.066 (−0.497, 0.365) | −0.012 (−0.445, 0.421) | −0.068 (−0.499, 0.362) | −0.075 (−0.507, 0.357) | |
| Average mother's hours per week on main job | 0.001 (−0.002, 0.0005) | 0.0001 (−0.0003, 0.0005) | 0.0002 (−0.0002, 0.0005) | 0.0001 (−0.0003, 0.001) | |
| Proportion of mothers in white-collar jobs | 0.006 (−0.004, 0.016) | 0.006 (−0.004, 0.016) | 0.006 (−0.004, 0.016) | 0.006 (−0.005, 0.016) | |
| Proportion of women in state legislature | 0.042 (−0.077, 0.160) | 0.037 (−0.081, 0.156) | 0.058 (−0.063, 0.179) | 0.045 (−0.074, 0.164) | |
| State party affiliation | |||||
| Republican | −0.002 (−0.013, 0.008) | −0.005 (−0.016, 0.006) | −0.004 (−0.015, 0.007) | −0.002 (−0.012, 0.009) | |
| Split | −0.007 (−0.016, 0.002) | −0.009* (−0.018, 0.0004) | −0.008* (−0.017, 0.001) | −0.007 (−0.016, 0.002) | |
| State fixed-effects | Yes | Yes | Yes | Yes | Yes |
| Year fixed-effects | Yes | Yes | Yes | Yes | Yes |
| Constant | 0.301*** (0.295, 0.308) | 0.296*** *0.182, 0.573) | 0.274*** (−0.004, 0.552) | 0.276* (−0.003, 0.555) | 0.290** (0.012, 0.569) |
| Overall R2 | 0.154 | 0.732 | 0.715 | 0.737 | 0.733 |
|
| |||||
| Observations | 1112 | 561 | 561 | 561 | 561 |
Note: Sample sizes vary across specifications due to item non-response on some variables. M3 includes the introduction year, and lags of 1–2 years, 3–4 years, and 5 years onwards. The first three indicator variables are equal to 1 only in the relevant year and the last indicator is 1 in each year, starting with 5 years after the year of adoption. In M4 the policy effect is split by enforceability. M5 includes leads of 5–6 years, 3–4 years, 1–2 years, and the main DID policy effect. States where the legislation is of weak enforceability (i.e. only encourage employers to provide facilities and/or break time) include Georgia, North Dakota, Oklahoma, Rhode Island, Texas, Virginia, Washington, and Wyoming. States where the legislation is of strict enforceability (i.e. requires employers to provide facilities and break time) include Arkansas, California, Colorado, Connecticut, District of Columbia, Hawaii, Illinois, Indiana, Maine, Minnesota, Mississippi, Montana, New Mexico, New York, Oregon, Tennessee and Vermont. 95% CI in parenthesis. The base level for state-party affiliation is Democratic. Coefficient estimates for state-fixed effects year dummies available upon request to authors. *p < 0·10; **p < 0·05; ***p < 0·01.