The size-growth relationship: a test of house price growth across the regions of the British Isles

Abstract

Purpose This paper aims to propose that a Neave-Worthington Match Test for Ordered Alternatives is a simple, non-parametric test that can be used to consider Gibrat’s law. Whether the law, that states that the proportional rate of growth is independent of absolute size, is supported by regional house price growth rates is considered. The Match Test is further used to test the applicability of beta-convergence and dual economy models to a house price context. Design/methodology/approach The Match Test relates an actual rank order with an expected one. Gibrat’s law implies house price growth rates are independent of the absolute price levels. Beta-convergence posits that growth rates are inversely related to the initial price level. With a divergent system, there is a direct relationship between size-order and growth rates. As such, the Match Test is used to test alternative models of size-growth relationship. Findings Rather than convergence, there is a tendency to diverge across the UK, but not in Eire. That said, the size of growth shocks is related to price level on the upswing of a price cycle, but not in the down. Assigning the high-priced regions of the two islands into core and the rest into a periphery, total matching is dominated by the capital cities’ growth. The sigma-convergence observed in British house prices is likely to be associated with slower beta-divergence, not a convergent system. The law of Gibrat is not found to apply in a regional house price context. Research limitations/implications This work only covers two countries and nineteen regions. Gibrat’s law in regional house prices may be better examined using a multi-country analysis. Practical implications As the law of Gibrat is not found to apply in a regional house price context and core-regions appearing to dislocated, this has interesting implications for growth trend analysis and the claim of cointegration, which should be explored further. In particular, the level-growth relationship in the cyclical price upswing points to a ratcheting of differentials between high and low house price regions. The common trends in the long run may result from corrective periodic crashes. Not an ideal mechanism for policymakers. Originality/value To the best of the author’s knowledge, this paper makes a novel use of the Neave-Worthington test in the realm of regional convergence-divergence and in the first consideration of the law of Gibrat in a house price context across two countries.