Download Al-Qaeda-related data from newspapers and Internet media sites. Since Al-Qaeda is not an official, legal organization, you must obtain information on it from news sources. Obtain as much of this information as you can possibly read during your research time frame.
Write a list of terror attacks associated with Al-Qaeda. Include any attacks mentioned in any report in which an expert (for example, a CIA official) was quoted as mentioning links to Al-Qaeda. Write the name of the persons or buildings targeted in each attack, as well as the country in which the attack took place.
Separate the list of attacks into three categories: certain, likely and uncertain. Under the "certain" category, place attacks claimed by Al-Qaeda. Under the "likely" category, place attacks that have occurred in areas where Al-Qaeda is known to operate and have targeted Al-Qaeda opponents. In the "uncertain" category, place attacks officials have listed as possibly linked to Al-Qaeda.
Add up the financial cost estimates for terror attacks for which Al-Qaeda was definitely or likely responsible. If no cost estimates exist for some of the attacks that have been attributed to Al-Qaeda, exclude these attacks from the calculations.
Tally up the financial costs associated with fighting Al-Qaeda. Review audit sheets for the Department of Homeland Security. Add up the costs on those sheets related to counterterrorism. Also add in cost estimate for war operations that can be directly linked to counterterrorism, if applicable.
State you conclusion on whether or not Al-Qaeda's main motive is financial. Estimate whether the cost from a) Al Qaeda attacks and b) counterterrorism efforts directed at Al-Qaeda would be sustainable. If your calculation suggest that they are not, you have corroborated (but not proved) the damage hypothesis. Of course, you must supplement this economic analysis with analysis of Al-Qaeda's methods, which cannot be tested scientifically.