Dynamic geometry software (DGS) has been around for decades; Geometer's Sketchpad (not the first, but probably the most well-known commercial product) has been around since 1986. Wikipedia lists more than thirty examples of the genre. I know that in the math ed literature there have been tons of studies (thirty years' worth, going back to the original research on the Geometric Supposer) on how DGS can be used (or misused) in teaching, on how students conceive of and interact with interactive diagrams, and on the factors (material and attitudinal) that constrain or enable teachers' adoption of this technology. But I have not found a straightforward answer to the following question: Just how many secondary geometry teachers actually use DGS, in some way, in their classrooms? Are we talking 20%? 50%? Less than 3%?
My own anecdotal experience seems to suggest that software of this type has only had limited penetration into the marketplace; that is to say, my impression is that most Geometry classes in most schools in the United States do not make any use of this software at all.
Of course "use DGS" can mean different things to different people. I imagine there are several different categories of DGS use:
- DGS software is not used at all
- DGS software is used occasionally, but only by the teacher, either for demonstration purposes or for creating static diagrams to include on printed documents like tests and worksheets
- DGS software is used occasionally by the whole class, but such use is limited to special projects or activities and not tightly-integrated into the rest of the curriculum
- DGS software is used consistently throughout the year and is tightly-integrated into the rest of the curriculum.
Ideally I'd like data that not only gives a single number for market penetration, but also gives some idea about how those adopters of the technology actually use it, either along the lines of the list above or using some other categorization. But frankly I'd settle for a simple number, even if it masks most of the important subtleties.