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

Abstract

Background: 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.

Methods: 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.

Results: 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%)).

Conclusions: 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.

Keywords: NIOCCS; NIOSH; birth certificates; coding; data quality; disparities; industry; occupation.