Employment Structure and the Rise of the Modern Tax System

This paper shows how the increase in information trails through the long-run transition from self-employment to employee-jobs explains the rise of the modern income tax system. I construct a new database which covers 100 household surveys across countries at different income levels and 140 years of historical data within the US (1870-2010). Using these data, I first establish four new stylized facts: 1) within country, the share of employees increases over the income distribution, and increases at all levels of income as a country develops; 2) the income tax exemption threshold moves down the income distribution as a country develops, tracking employee growth; 3) the employee share above the exemption threshold is maximized and remains constantly high; 4) decreases in the exemption threshold are strongly associated with increases in tax collection. These findings are consistent with a model where a high employee share is a necessary condition for effective taxation and where the rise in income covered by information trails through increases in employee share drives expansion of the income tax base. To provide a causal estimate of employee share on income tax systems, I study a state-led US development program implemented in the 1950s-60s which increased the level of employee share. The identification strategy exploits within-state changes in court-litigation status which generate quasi-experimental variation in the effective implementation date of the program. I find that the exogenous increase in employee share is associated with an expansion of the state income tax base and an increase in state income tax revenue.