18
military aid, military training operations, the forward deployment of military troops, the
evacuation of military or civilian personnel and disaster relief.
3
The dependent variable in the statistical analyses is intervention outcome, which can be
interpreted as the probability that a major power state will achieve its primary political objective
when it uses military force abroad. The coded variable is dichotomous and takes a value of one
when the state attains its primary political objective and that objective is maintained for at least
one year after the intervention is terminated, and zero otherwise (Blechman and Kaplan 1978).
This coding rule was adopted so that only interventions which resulted in a meaningful foreign
policy achievement were considered “successful”. Intervention outcome equals 1 (attain) in 61%
of the cases. Raising and lowering the standard for how long an objective had to be maintained
for the intervention to be considered a success had little impact on the statistical results. In
general, lowering the standard to six months decreased the marginal effect of target vulnerability
while raising the standard to three years increased the effects of both target vulnerability and
political objective type (results not shown).
The key explanatory variable in this model is the degree to which the intervening state’s
primary political objective is dependent versus unilateral at the initiation of the intervention. In
order to facilitate rigorous coding of the political objective and outcome of each intervention, I
created ten political objective categories based on an historical analysis of the universe of cases.
Next, I used a team of four research assistants to research the political objectives of the major
power state in each case and to code each case according to the category that best represented the
state’s primary war aim. The appendix contains a list of the political objective categories.
Finally, I created a series of three dummy variables to capture the nature of the major power
state’s primary political objective in each case. A state’s objective is considered to be
3
For detailed information about data collection and coding see Sullivan (n.d.).
Convention