I'm certainly not claiming that quantitative research should be thrown out the window or that qualitative research should be embraced exclusively; I think that a balance between the two is what is needed in almost all situations, for almost all research topics. I'm sure a more complete exploration of all of my questions logged in my head or jotted in the margins would make the book prohibitively ponderous (certainly beyond the scope of a light pop-science read), and in some cases the investigation of why might have proven prohibitively difficult, but I would have preferred it, at least. :~)
I'm happy to report that the authors revisit the theory they put forth in the introduction that legalized abortion was a dominant cause of the mid-nineties crime-drop, and included a lot more information than they gave in the (rather inflammatory) introduction or in other online debates. They also have a whole chapter on the rise and fall of the crack epidemic, a critic's key argument against them.
In addition, they discuss cheating among teachers and sumo wrestlers, the KKK and real estate agents, and naming - a self-proclaimed hodgepodge of topics. Yet I did detect a common theme, one that affects both authors personally: parenting. The first chapter on cheating is a set-up of some basic economic principles (and incidentally discusses schools and standardized tests, which are often of great concern to many parents), and the second introduces some effects of asymmetric information. The chapter on gangs and crack leads in to the next chapter, which is on abortion and crime - and it's here that anecdotal parenting stories start to give way to more lengthy discussion on parenting choices. The next two chapters are explicitly about parenting: which factors matter, which do not, and which may just be left for parenting experts to banter about forever. The last chapter is about baby naming, another very parent-oriented topic.
Despite the focus on parenting, I don't know if I would get this for the new parents among my family or friends. (I was thinking that my own parents, one of whom has a newborn and both of whom will be grandparents soon, might enjoy it, but maybe I could just lend them my copy.) I'm afraid that they will succumb to something we all do on occasion (some more than others), and which the book does a terrible job at allaying: number obsession. So many people worry that they're in a category that statistically performs worse than another category, even when they're actually an anomaly anyway. I've read elsewhere about our increasing obsession with statistics, and I've read about how it can be unhealthy - I would hate to foster it. :~)
Curiously, the authors echo Michael Moore's discussion topics in Bowling for Columbine in their discussions of guns (swimming pools are more dangerous to kids on average), fear (the KKK and real estate agents both use it, along with information asymmetry, to their advantage), and race (pervasive through their discussions of abortion, crime, crack, schools, names, and parenting). A choice quote (are they referring to themselves, too?):
An expert doesn't so much argue the various sides of an issues as plant his flag firmly on one side. That's because an expert whose argument reeks of restraint or nuance often doesn't get much attention. An expert must be bold if he hopes to alchemize his homespun theory into conventional wisdom. His best chance of doing so is to engage the public's emotions, for emotion is the enemy of rational argument. And as emotions go, one of them - fear - is more potent than the rest. The superpredator, Iraqi weapons of mass destruction, mad-cow disease, crib death: how can we fail to heed the expert's advice on these horrors when, like that mean uncle telling too-scary stories to too-young children, he has reduced us to quivers? ... Most of us are ... terrible risk assessors. ... "Risks that you control are much less a source of outrage than risks that are out of your control," Sandman said. ... So it's the imminent possibility of death that drives the fear. ... But fear best thrives in the present tense. That is why experts rely on it; in a world that is increasingly impatient with long-term processes, fear is a potent short-term play. [excerpts from pages 148-151]