Are Suicide Rate Fluctuations Transitory or Permanent? Panel KSS Unit Root Test with a Fourier Function through the Sequential Panel Selection Method

The purpose of this study is to examine whether suicide shocks are transitory or permanent in 23 OECD countries. The Panel KSS Unit Root Test with a Fourier Function through the Sequential Panel Selection Method (SPSM) that allow us to control for structural breaks and nonlinearity as well as cross-section dependency and heterogeneity is applied to test whether suicide rates across 23 OECD countries for the period from 1961 to 2006 are stationary. The SPSM classifies the whole panel into a group of stationary series and a group of non-stationary series that is very suitable to identify how many and which series in the panel are stationary processes. The empirical results from several conventional unit root tests indicate that the suicide rates for the OECD countries are non-stationary. Nevertheless, when the proposed panel unit root test is used to test for the unit root hypothesis of suicide rates, we find that the suicide rates are stationary in 7 out of the 23 OECD countries. Our results thereby point out the importance of the proper modelling of both structural breaks and nonlinearities to test for the unit root hypothesis of suicide rates. These findings also imply that suicide rates in these OECD countries are overall not transitory and the government should progressively intervene into unexpected shocks that would increase suicide rates for suicide prevention.