New Framework Refines How Wage Gaps are Attributed
A generalized decomposition method shows that nonlinear controls significantly shift the perceived drivers of wage dispersion.
The Generalized AKM framework allows economists to determine whether wage differences stem from worker skill, firm-level pay scales, or the way workers sort into specific companies using nonlinear controls. By moving beyond linear adjustments, the model isolates the true variance of these components without the bias inherent in traditional fixed-effects models.
This shift in measurement changes the perceived distribution of labor costs. In a test using Portuguese employer-employee data, the inclusion of worker and firm-input controls reduced the attributed worker-effect variance from 0.551 to 0.474 of total wage variance. Firm-effect variance dropped from 0.144 to 0.121, while sorting—the premium paid for matching specific workers to specific firms—fell from 0.080 to 0.047.
For industries where human capital is the primary asset, this precision alters the understanding of competitive advantage. If sorting variance is lower than previously thought, the ability of a firm to "cherry-pick" high-productivity talent for a premium is less of a driver of wage dispersion than the baseline pay scales the firms set.
Companies managing large-scale workforces may find that their internal pay disparities are driven more by firm-wide policies than by the specific characteristics of the employees they hire. The research shows that which controls are used matters more for firm variance and sorting than the mathematical flexibility of those controls.
This methodology provides a more accurate lens for analyzing labor market frictions and wage rigidity. When the worker-effect variance remains sensitive to the basis of the controls, it suggests that the perceived value of individual worker skills is highly dependent on how those skills are measured against firm inputs.
Labor economists and policy analysts can now better distinguish between systemic firm-level pay disparities and individual merit. This distinction is critical for assessing the impact of minimum wage shifts or collective bargaining agreements on overall market variance.