Abstract. This paper undertakes to explain the relationship between EU accession and the length of business cycles, focusing specifically on whether participation in a multinational organization has, or has not, altered the length of the cycle. Employing a sample of nine EU countries (Austria, Denmark, Finland, Greece, Ireland, Portugal, Spain, Sweden and the UK) we focused initially on annual data for per capita growth in GDP over a period of 59 years (1950-2008). For each country the sample was divided into two parts, one covering the period preceding accession to the EU and one is covering the accession year and succeeding years. Then, eliminating the background noise with the use of a periodogram, we proceeded to examine their spectral density plots. The results indicated that in the first years following accession, the countries tended to experience shorter cycles than they had previously. In the second phase the cycles were of the same duration as previous cycles. Finally, after a period of some years, the length of the cycles increased, as suggested by the J-shaped curve. This J-shaped growth curve applies for the countries that have joined the EU, strongly suggesting a causal relationship between accession to the EU and these specific characterristics of the curve. We cross-checked with a set of four non-EU member countries (Iceland, Norway, Switzerland and Turkey) and found no change in the length of the business cycle in these countries.

Keywords: economic integration; business cycles; European Union.