Industry and occupation in California birth certificates (1998-2019): Reporting disparities and classification...

Missing and noncodable parental industry and occupation (I/O) information on birth certificates (BCs) can bias analyses informing parental worksite exposures and family economic stability.

We used the National Institute for Occupational Safety and Health (NIOSH) software to code parental I/O in 1989-2019 California BC data (N = 21,739,406). We assessed I/O missingness and codability by reporting period, parental sex, race/ethnicity, age, and education.

During 1989-2019, records missing I/O increased from 4.4% to 9.4%. I/O was missing more frequently from parents who were male (7.8% vs. 4.4%), Black or American Indian/Alaska Native (AIAN) (9.3% and 8.9% vs. 3.2%-4.7% in others), and had high school or less education (4.0%-5.9% vs. 1.4%-2.6% in others). Of records with I/O, less than 2% were noncodable by NIOSH software. Noncodable entries were more common for parents who were male (industry (1.9% vs. 1.0%); occupation (1.5% vs. 0.7%)), Asian/Pacific Islander (industry (2.4% vs. 1.2%-1.6% in other groups); occupation (1.7% vs. 0.7%-1.5% in other groups)), age 40 and older (industry (2.1% vs. 0.4%-1.7% in younger groups); occupation (1.7% vs. 0.3%-1.3% in younger groups)), and 4-year college graduates (industry (2.0% vs. 1.0%-1.9% in other groups); occupation (1.7% vs. 0.5%-1.4%)).

In California BC, I/O missingness was systematically higher among parents who are male, Black, AIAN, less than 20 years old, and report no college education. I/O codability is high when information is reported, with small percentage disparities. Improving data collection is vital to equitably describe economic contexts that determine important family outcomes.