CHICAGO (AFP) - Public opinion polls are good predictors of terrorist attacks, according to a study published Thursday, which argues that terrorists do not act independently of their countrymens attitudes. US researchers studied surveys from 19 countries in the Middle East and North Africa in which people were asked whether they approve or disapprove of the job performance of foreign leaders. They compared those results with the number of terrorist attacks committed by people and groups from the surveyed countries against the United States, the United Kingdom, Russia, Germany, France, Canada, Japan, China and India. They found that a 20 percentage point increase in the disapproval rate of a countrys leaders was associated with a 93 percent increase in the number of terrorist attacks originating from a particular country. Poverty levels and the opinions of youth aged 15 to 24 often considered potential factors leading to terrorist activities were not good predictors of terrorist attacks, the study published in the journal Science found. Greater disapproval of another countrys leaders and policies could result in more terrorist incidents for at least two reasons, wrote lead author Alan Krueger, a professor of economics and public policy at Princeton University. On one hand, it could increase the number of people in a society who provide material support and encouragement for terrorist cells, he wrote. It is also plausible that international terrorism is greeted with greater legitimacy as the level of disapproval increases and that a shift in public disapproval could increase the number of people willing to join terrorist cells and carry out terrorist acts themselves. Krueger noted that public opinion toward other countries is influenced by many factors, including historical animosities, religious rivalries, and economic competition. He argued that leadership is nonetheless important and suggested that changes in leadership and public policy may well lead to a reduction in public disapproval. For example, the election of Barack Obama who opposed the war in Iraq, criticised the use of torture and detention of alleged terrorists at Guantanamo Bay, and offered to engage in 'aggressive personal diplomacy with leaders of Middle Eastern countries such as Iran may well lead to a reduction in public disapproval toward the leadership of the United States. The study analyzed opinions in Afghanistan, Algeria, Cyprus, Egypt, Iran, Israel, Jordan, Kuwait, Lebanon, Mauritania, Morocco, Pakistan, the Palestinian territories, Saudi Arabia, Sudan, Tunisia, Turkey, the United Arab Emirates, and Yemen recorded by the Gallup World Poll in the 2006 and 2007. Krueger was appointed Assistant Secretary for Economic Policy at the US Department of Treasury after the study was submitted. Science noted that the contents of the paper do not necessarily represent the position of the US government.