Two identical firms that start exporting in different months, one each in January
and December, will report dramatically different exports for the first calendar year.
This partial-year effect biases down first year export levels and biases up first year
export growth rates. For Peruvian exporters, the partial-year bias is large: first-
year export levels are understated by 54 percent and the first year growth rate is
overstated by 112 percentage points. Correcting the partial-year effect dramatically
reduces first year export growth rates, raises initial export levels and almost doubles
the contribution of net firm entry and exit to overall export growth.