What Today's Buggy Article Is Up To
In this, the 5th buggy article in a strung-out series on Professor Robert Pape's nationalist theory of suicide terrorism, our focus narrows and attaches itself determinedly, with single-minded thrusts, on the statistical effort by Pape to test his nationalist theory of suicide terrorism by means of a logit regression model.
Pape himself makes various claims for the data-base that he himself gathers, codes, and organizes and for the estimated effects of the logit models that he then specifies to analyze the data-set. It's on pages 96 and 97 of Dying to Win that these claims first appear:
To test my theory, Pape writes, I employ a methodology that combines the features of focused-comparison and statistical-correlative analysis using the universe of foreign occupations, 1980-2003. Correlative analysis of this universe [by means of a logit model] enhances confidence that my theory can predict future events [of suicide terrorism] by showing that the patterns predicted by the theory actually occur over a large class of cases. Detailed analysis of historical cases enhances confidence that the conclusions found in the larger universe are not spurious --- that is, that my theory accurately identifies the causal dynamics that determine outcomes.h
Note Pape's Words Carefully
The correlative analysis of what he identifies later as a logistic regression model using logit analysis --- the two terms are roughly interchangeable --- will do two things: it will enhance confidence . . .
- That his nationalist theory of suicide terrorism has accurately identified the causal dynamics of suicide terrorism that occurred during all foreign [military occupations] between 1980 and the end of 2003 --- which turn out to be 58 such cases in all, or so he later insists. Note in passing that these 58 cases are then coded and organized into data that correspond, as we'll soon see soon, to the dependent and independent variables in his logit model(s) and become its sample selection that the model than is run on.
- And that, in turn --- thanks to these accurately identified causal dynamics --- his theory can predict suicide terrorist attacks.
The Buggy Take Here
As we'll see, Pape is flat-footedly wrong. His data-set and the estimated logit model's reported outcomes --- to the extent Pape provides any information at all about them (p. 99 and fn. 43, p. 294) --- do not enhance our confidence whatsoever. They do the exact opposite, and for reasons set out at length in today's substantive argument.
How That Buggy Argument Will Unfold in Three Parts.
In Part One, We'll summarize anew Pape's nationalist theory of suicide terrorism --- especially its alleged causal links --- and cap the summary by reproducing the schematic diagram that appears on p. 96 in Dying to Win. Even if you've read the previous buggy article that performed both of these tasks, the comments here will likely help jog your memory again.
Enter Part Two. We'll examine Pape's logit model in depth there. In particular, we'll try to reproduce how Pape likely specified it, assuming he followed a proper statistical procedure, including its variants. We'll also look at his very scantily reported regression outcomes. Remember, with such stingy information, some conjecture is inevitable --- but most likely, sound conjecture.
Part Three is the key to the buggy argument, a matter of analysis and criticism --- mainly the latter.
Two More Preliminary Comments To Keep in Mind:
1. If you have no understanding of linear regression modeling and how logistic regression differs from it, be sure to read the previous buggy article. It sets out a series of fairly straightforward, easy-to-grasp comments about the nature of linear regression, how logistic regression differs from it, and why Pape had to use the latter to test his theory of suicide terrorism: the use of a binary qualitative variable as the dependent or output variable --- what he3's trying to account for, given a set of independent or explanatory variables that he specifies in his logit model. (Remember, logistic regression and the logit model (or logit analysis or transformation) are roughly but not exactly interchangeable terms).
2) More to the point, the buggy analysis that will unfold here cannot avoid using a fair amount of statistical terminology. You may have already suspected this. Despite prof bug's best efforts, there's no help for it. To avoid the technical terms, it would be necessary to expand the article several-fold in length order to clarify each point effectively.
Even so, prof bug urges you not to give up if some of the criticisms he makes of Pape's statistical work elude your understanding. Keep reading on. The main problems in any case derive from fairly easy-to-understand matters, specifically:
* The defects in Pape's data-set, which is his sample selection for the logit model he specifies, are numerous, and it will be easy to grasp them.
* Pape claims for what his logit model will do --- enhance our confidence in his theory of suicide terrorism, give us confidence about its predictive value for the future, and so on --- are not at all justified by his statistical work, starting with the data-set itself and with all the problems that hound his model's specification, interpretation, and reported statistical tests. The hollow nature of these claims will easy to grasp as the buggy argument unfolds.
*Finally, we'll end by some explicit and more general problems that beset regression modeling, linear or otherwise, in the social sciences . . . particularly claims made by the slew about how such modeling establishes causal links and predictive powers of the various theories that social sciences claim to be testing.
PAPE'S THEORY OF SUICIDE TERRORISM SUMMARIZED ANEW
Chapter Six Takes Center Stage
It's in chapter six of Pape's book (pp. 79-101) that a full-fledged theory of suicide-terrorism emerges for the first time.
To Pape's credit, his "nationalist theory of suicide-terrorism is set out clearly there and discussed in useful detail. It consists of four component parts --- a set of independent or explanatory variables if you prefer, all intended to clarify the circumstances that will likely "cause" suicide attacks to be launched. Pape refers to them as "causal" influences. It's those four that form the basis of his logistic regression exercise, a logit model intended to "test" his theory's postulated "causal" pathways that lead to suicide terrorism.
The latter pathways, as you'll see, are juggled around and summarized by Pape himself in a schematic diagram that is found on p. 96 and that will be reproduced at the end of this buggy part.
The Four Independent ("Causal") Variables Sketched In
Sketched in is the key term here.. The four independent (estimating) variables are set out in a fast, top-skimming manner, at any rate for now. The aim is to give you a rough working idea of each variable, followed by the schematic diagram; nothing more . . . not for today anyway. It's only in the next buggy article, remember, that each of these alleged causal links and pathways will be delved into at length.
As for the use of quotes around causal, they're there purposefully. Pape's theory isn't a scientific theory in a strong sense we'll see, rather more like a wiring diagram with arrows drawn in different pathways to signify hoped for causal pathways among the variables. And very few regression models, linear or non-linear, cannot test causally any theory except a few in the natural sciences.
As we'll also see, even the most formalized economic regression-models running on strictly quantitative data that can be randomly sampled have never been tested accurately for any causal links --- even, believe it or not, neo-classical demand theory, the core of microeconomic theory. For a good 75 years now, econometricians have been trying to test the various empirical variables in demand theory --- the symmetry of (compensated) Slutsky matrix, the homogeneity of degree zero of individual and aggregate demand functions, and Walrus Law (adding up or Engle aggregation), and guess what? Almost all tested statistical models have produced results that contradict the theory of demand. (See the discussion of this on pages 96-98 in D. Wade Hands, Reflections Without Rules; Economic Methodology and Contemporary Science Theory [Cambridge, 2001). The quoted terms are from pp. 96-97)
So Where Are We?
All these points will be clarified later on in Part Three. For the moment, fasten your attention on the independent variables that comprise Pape's nationalist theory of suicide terrorism.
1) There's an alien military occupation on a territory of another people --- a national or ethnic community that resents it --- by a democratic country. Pape says that he can find no cases where suicide terrorism has been used against non-democratic occupiers.
Note in passing that this particular variable doesn't enter into Pape's logit model per se. It's not even an exogenous variable, operating from the outside on the logistic regression estimates of the outcome variable and the coefficients of the estimating variables. Instead, by definition, Pape limits his data-collection and coding to only democratic occupying countries . . . wrongly so, as we now know and as will be clarified in part three.
2) Sooner or later, a noticeable religious conflict between the occupying power and the occupied population has to develop that aggravates the locals' fears and resentments of the occupier and leads to demonizing its society and civilians. In turn, the demonizing will celebrate national martyrdom by armed rebels against the evil occupier, justifying the use, if need be, of suicide terrorism . . . the latter seen by more and more of the occupied people as a last desperate resort at coercing the alien democratic country to withdraw its military forces.
Note: though prof bug has striven hard to refrain from critical comments of Pape's theory until the next buggy article in this series, he can't, alas, fully adhere to this self-denying ordinance here.
More specifically, if Pape is right, the fact that one religion --- Islam, which constitutes most of the suicide terror campaigns between 1980 and 2003 even in his flawed and understated data-set that appears on p. 15 of his book, and 7 of 9 such suicide-terrorist campaigns that he himself codes in appendix two (pp. 265-67) --- has a 1300 year-tradition of armed martyrdom suffered in jihad against infidels, with the suicide attackers instantly entering Paradise the second after they're killed, where they can now enjoy worldly pleasures for eternity without guilt, has nothing to do per se with such demonizing or justification of suicide attacks. Nor does it have anything to do with Islamist terror groups carrying out 90% of the suicide attacks between 1980 and 2003, at any rate when Pape whitewashed data-set is corrected(A table of all the suicide attacks by radical Islamist groups --- mainly against Muslim countries --- that Pape omits or conceals appeared in two earlier buggy articles: the one immediately preceding this one, and the 2nd one in this series on Dying to Win.
Then, too --- if there isn't something specific to Islam compared to, say, Christinaity or Judaism --- why is that Palestinian suicide terrorism against Israelis has been going on now for 11 years by now, yet not one Christian Palestinian has engaged in the more than 500 suicide terrorist attacks launched from the West Bank and Gaza? Christians comprise about 10% of the total Palestinian population. If it's nationalist fervor that is the driving force of suicide terrorism, why then wouldn't Christian suicide terrorists account for about 10% of the total? Yet far from that being the case, there's not one suicide attack that originated out of the Christian minority.
(Pape does show, revealingly, that 3 of the 41 sucide attackers operating in Lebanon in the 1980s --- almost all under the auspices of Hezbollah and with the attack directed at French, American, and Israeli forces --- were Christian. Revealing, too --- after supplying this informative statistic on p. 205 --- he provides a radically misleading pie chart that shows Christains comprising 71 % of the 41 bombers. Usually, 3/41 equals 7.3%, not 10 times that number.
Since Christians in Lebanon were about 50% of the country's total population, the odds that a Christian would participate in a suicide attack were roughly 1/6th of the odds that a Muslim would participate. Still, the most illuminating point is that there is no record of a Christian suicide terrorist in the Palestinian community since 1994, the year that Hamas --- richly financed by Saudi oil-money to further Wahhabi Islamism (not that Pape tells us this) --- began its suicide operations.)
All this, understand, before 2004.
If you add in the suicide terrorist attacks carried out by Islamist radicals since then --- including such target countries as Spain, Britain, Turkey, Egypt, Tunisia, Morocco, Indonesia, the Philippines, Iraq, Israel, and Russia among others --- you'll get hundreds more, not to mention the hundreds of attempted suicide attacks that have been thwarted by European, American, Russian, Arab, and Israeli security forces. Note that the buggy table referred to a moment ago will be reproduced later in this article, when we examine Pape's coded data-set itself)