The impact of special economic zones on export behaviour. Evidence from Polish firm-level data

Special economic zones play an important role in the global economy and in the economies of particular countries, including Poland. Given the whole body of literature on SEZs-led export activity, the vast majority of papers, restrict the research methods used to the descriptive analyses or the case studies of specific zones, only describing the impact thereof on the national economy. The existing empirical evidence (econometric) in the vast majority of papers associated to zonal operation does not account for the endogeneity bias, which can have a distorting effect on the results. Nevertheless, little is known about the real (based on solid evidence) SEZ influence on the firm-level characteristics, with regard to the creation of exports. The role of SEZs in relation to firm-level export probability/scale/intensity/volume has been investigated using a unique dataset for 155 firms operating in special economic zones (SEZs) in Poland, accompanied by the data for 155 non-SEZs economic entities (matched sample). With the use of different estimation techniques, conditioned by the uneven nature of the tested dependent variables, a positive role of SEZs was found in relation to certain aspects of the firm-level exports. The possible endogeneity problem in the SEZ variable was properly addressed by utilising a kernelbased propensity score matching difference-in-difference estimator and by calculating the average treatment effect on the treated (ATT), accompanied by a series of robustness/sensitivity tests (changes in kernel type, bandwidth, dataset trimming). The results provide consistent evidence on the effect of the SEZs on export probability in firms operating within the zones, as compared to the control group. The positive impact of the SEZs on the scale of exports, export intensity and the volume of exports was however sensitive to dataset trimming. Hence, the impact of the SEZs operation in this regard could not be full acknowledged