lograndd[InstInnovation$lograndd == -Inf] &lt;- 0

## regression formulas
f1 &lt;- cites ~ institutions + log(capital/employment) + log(sales) + industry + year
f2 &lt;- cites ~ institutions + log(capital/employment) + log(sales) +
  industry + year + lograndd + drandd
f3 &lt;- cites ~ institutions + log(capital/employment) + log(sales) +
  industry + year + lograndd + drandd + dprecites + log(precites)

## Poisson models
tab_I_3_pois &lt;- glm(f1, data = InstInnovation, family = poisson)
tab_I_4_pois &lt;-