THE EFFECTIVENESS OF ANTITERRORISM POLICIES - A VECTOR-AUTOREGRESSION-INTERVENTION ANALYSIS

Using quarterly data from 1968 to 1988, we analyze the time series pro perties of the various attack modes used by transnational terrorists. Combining vector autoregression and intervention analysis, we find str ong evidence of both substitutes and complements among the attack mode s. We also evaluate the effectiveness of six policies designed to thwa rt terrorism. The existence of complements and substitutes means that policies designed to reduce one type of attack may affect other attack modes. For example, the installation of metal detectors in airports r educed skyjackings and diplomatic incidents but increased other kinds of hostage attacks (barricade missions, kidnappings) and assassination s. In the long run, embassy fortification decreased barricade missions but increased assassinations. The Reagan ''get tough'' policy, which resulted in the enactment of two laws in 1984 and a retaliatory raid o n Libya in 1986, did not have any noticeable long-term effect on curbi ng terrorist attacks directed against U.S. interests.