Using quasi-experimental designs for causal effects

Abstract

Purpose: This paper discusses the concept of identifying the causal effects using quasi-experimental methods and applies this method to investigate the impact of high license fees on the quality of mobile Internet in Poland. Design/methodology/approach: Quasi-experiment design, especially the difference-in-differences method and the interrupted time series design were used to examine the causal effects of spectrum fees in Poland. Data on the quality of mobile Internet in Poland and around the world published by Akamai and data provided by Ookla® under the agreement were used for analysis. Findings: The study did not confirm the impact of high spectrum fees on the quality of the Internet in Poland. Practical implications: The results obtained can help policymakers in Poland and other countries in making decisions on spectrum management. Originality/value: This is the first paper using the quasi-experimental method to examine the effects of the 4G auction in Poland. Keywords: quasi-experiment, difference in difference (DiD), interrupted time series design (ITS), spectrum auction, mobile Internet market. Category of the paper: Research paper.