California

Pesta standardized PIAAC literacy/numeracy and 2015, 2017, and 2019 NAEP reading/math state scores, derived separate PIAAC and NAEP estimates, and averaged them.

• This is an ecological proxy built from achievement and adult-skills assessments, not a representative IQ test of every resident.
• The source populations, years, constructs, and sampling frames differ.
• Do not infer an individual's ability from a state aggregate or treat small state differences as precise.

Uncertainty: The article reports a point estimate but does not provide a state-specific confidence interval in Table 2.

NCES reports results from nationally representative samples using common NAEP assessment frameworks.

• NAEP measures educational achievement and is not an IQ test.
• Grade, subject, accommodations, exclusions, and sampling error must remain visible.

Uncertainty: No numeric value is frozen because subject, grade, statistic, and plausible-value uncertainty must be selected together.

NCES combines PIAAC survey data with auxiliary small-area data to produce state and county estimates.

• Small-area estimates are modeled, not direct tests of all state residents.
• Literacy and numeracy are distinct skills and should not be collapsed into IQ.

Uncertainty: A numeric value is withheld until domain, estimate type, model release, and interval are versioned.

The Census Bureau weights ACS survey responses to estimate population characteristics.

• Educational attainment is not cognitive ability.
• ACS estimates require margins of error and exact table universes for valid comparisons.

Uncertainty: No percentage is frozen without its ACS table, universe, release, estimate, and margin of error.