 glm(f2, data = InstInnovation, family = poisson)
tab_I_5_pois &lt;- glm(f3, data = InstInnovation, family = poisson)

## one-way clustered covariances
vCL_I_3 &lt;- vcovCL(tab_I_3_pois, cluster = ~ company)
vCL_I_4 &lt;- vcovCL(tab_I_4_pois, cluster = ~ company)
vCL_I_5 &lt;- vcovCL(tab_I_5_pois, cluster = ~ company)

## replication of columns 3 to 5 from Table I in Aghion et al. (2013)
cbind(coef(tab_I_3_pois), sqrt(diag(vCL_I_3)))[2:4, ]
cbind(coef(tab_I_4_pois), sqrt(diag(vCL_I_4)))[c(2:4, 148), ]
cbind