Discussion Papers

Martin O. Wengler, Ralf G. Schäfer

Substitutionsbeziehungen zwischen Festnetz und Mobilfunk: Empirische Evidenz für Deutschland und ein Survey internationaler Studien
Nr. 249 / Dezember 2003


At the beginning of the 1990’s mobile phones were expensive, technically less sophisticated goods, which were predominantly used by business customers. After the adoption of the digital GSM-technology the demand for mobiles increased rapidly. With the significant decline of the mobile charges during the nineties, cellular phones became a mass market and today there are more registered mobiles than fixed-lines in Germany. Considering this development the question becomes crucial, whether fixed-lines and mobiles are substitutes or complementary goods.

There are only few empirical studies which scrutinised the German telecommunications market for substitution issues in a scientifically based way. Previous studies on the fixed-mobile substitution mostly used descriptive statistical methods or integrated the German telecommunications market in a cross-country panel data set. Thus, empirical evidence on fixed-mobile substitution in Germany is rather poor. The present study therefore aims at narrowing this lack of suitable information. On the one hand we investigate the German telecommunications market with primary data for fixed-mobile substitution. To this end reliable and representative survey data on residential and on business customers is evaluated with analytical statistical methods. This analysis aims at describing and explaining, in which way different customer groups use and perceive fixed and mobile telephone services. On the other hand we give a survey on econometric international country studies. Thereby we give an overview of different methodological approaches to deal with the issue of fixed-mobile substitution. Furthermore we compare the empirical findings for Germany with the international ones.

The present study reveals detailed information on three topics related to the substitution issue:

  • Use and awareness of mobile and fixed-line services for different groups of customers (residential customers and enterprises) in Germany,
  • Fixed-mobile substitution in foreign countries,
  • Prospects for further research related with the substitution issue.

Our analysis shows certain evidence of fixed-line substitution by mobiles in the German telecommunications market. However the effects scale only on a low level today. If we compare the empirical findings for Germany with other developed countries, it can be expected that the substitution issue will gain importance in a medium term perspective. It is highly likely that fixed-mobile substitution is going to exert a significant influence on competition and market structure in the German telecommunications market. [full version only available in German]

Diskussion Paper is available for download.

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