Model

Data Generating Mechanism

This analysis examines the relationship between county characteristics and AI job intensity using the following specification:

\[AI\_{it} = \alpha_i + \gamma_t + \beta_1 STEM_{i,t-1} + \beta_2 Tightness_{i,t-1} + \beta_3 Manufacturing_{i,t-1} + \beta_4 X_{i,t-1} + \varepsilon_{it}\]

Where: - \(AI_{it}\) is the share of AI-related job postings in county \(i\) at time \(t\) - \(\alpha_i\) are county fixed effects - \(\gamma_t\) are year fixed effects
- \(STEM_{i,t-1}\) is the lagged share of STEM degrees - \(Tightness_{i,t-1}\) is lagged labor market tightness - \(Manufacturing_{i,t-1}\) is lagged manufacturing employment share - \(X_{i,t-1}\) represents other lagged county characteristics - \(\varepsilon_{it}\) is the error term

Key Modification: Population Weighting

The critical methodological contribution examines how results change when observations are weighted by log(population):

\[w_i = \log(Population_i)\]

This weighting scheme gives more influence to larger counties in the estimation, potentially changing the interpretation of results from a county-centric view to a population-centric view.

# A tibble: 8 × 7
  term                 estimate std.error statistic   p.value conf.low conf.high
  <chr>                   <dbl>     <dbl>     <dbl>     <dbl>    <dbl>     <dbl>
1 Intercept            -1.86e+3   1.35e+2    -13.8  1.13e- 42 -2.12e+3  -1.59e+3
2 Bachelor's share     -1.35e+3   1.72e+2     -7.88 3.68e- 15 -1.69e+3  -1.02e+3
3 Labor Tightness       2.83e-2   2.40e-4    118.   0          2.78e-2   2.87e-2
4 Patents per employee  1.13e+5   6.75e+3     16.8  2.88e- 62  1.00e+5   1.27e+5
5 STEM share            1.41e+3   3.87e+2      3.64 2.75e-  4  6.50e+2   2.17e+3
6 Manufacturing inten…  1.03e+3   1.61e+2      6.43 1.37e- 10  7.18e+2   1.35e+3
7 ICT intensity         2.77e+4   1.07e+3     25.8  7.87e-141  2.56e+4   2.98e+4
8 Turnover rate         1.18e+4   1.20e+3      9.84 1.00e- 22  9.46e+3   1.42e+4