Highly Recommended Reading by Clark, Kirschner, and Sweller in American Educator Magazine: "Putting Students on the Path to Learning: The Case for Fully Guided Instruction".
I suppose that the "math wars" of the 1990's aren't entirely over yet. For example, for several years I've gotten this one magazine every other month called the NEA Higher Education Advocate (which in this household is referred to as "the crappy teaching magazine"). Every edition has a central keynote article under the heading of "Thriving in Academe", which almost uniformly features a call to "reform" type instructional techniques such as group-work projects, exploratory/discovery-based learning, and the like. When it comes in every other month, I tend to say, "Ah, the Pravda has arrived."
Among the funny recurring jokes of the feature is that it always has a "Issues to Consider" section (FAQ, basically), which frequently fields the question of "Won't this take more time and effort/ Not allow us to cover as many topics?" And the answer is usually some flavor of "Definitely!". For example, from the Dec-2008 article on "CRISP" (there's usually someone peddling a new acronym/system in every issue):
Won’t being C.R.I.S.P. cause me to sacrifice coverage?
Of course. The sciences are especially concerned with complete nomenclature. They are worried that if a Biology 101 student doesn’t learn every bone, muscle, and organ in the body, the student won’t be prepared for Biology 102, not to mention advanced study in related fields such as nursing and exercise and sports science. However, since studies indicate that students will “forget” (they actually put the information in their short-term memories only) 75 to 90 percent of the material in three months anyway, shouldn’t you worry more that students develop skills and fundamental concepts? If students truly comprehend, for instance, how the bones work in general, shouldn’t they be able to figure out how a specific bone functions or know where to look it up?
So in contrast, the American Educator magazine is what I call the "good teaching magazine" and seems to have much higher-quality, more in-depth, and more interesting articles in each issue (it's published on a quarterly basis). The current "Fully Guided Instruction" article by Clark, et. al. was a bracing breath of fresh air, representing the opposite point of view, that attempting to have students "discover" principles on their is a weaker technique than instructors cutting to the chase and simply telling them how things work in a straightforward manner (and modeling proper usage, and then overseeing practice). It cites seemingly strong research that the two techniques can be appropriate for different groups of students: in particular, strong students (with pre-existing deep background knowledge) work well with discovery-based learning, whereas weak students (those with deficiencies) do better with explicit direction. In fact:
Worse, a number of experiments found that less-skilled students who chose or were assigned to less-guided instruction received significantly lower scores on posttests than on pretest measures. For these relatively weak students, the failure to provide strong instructional support produced a measurable loss of learning.
So this seems particularly relevant to my work, over half of which is teaching remedial arithmetic and algebra at a large, urban community college (the stats for us, and nationwide, being about 60% of students taking remedial math, and only about 30% successfully completing it after 3 years).
And the other fascinating thing in the article was the description of a decades-long history of similar "discovery-based" reform efforts since at least the 1950's, each of which have been given a new name and similarly came up empty with research-based results for it. Highly recommended reading.