SPR Numbers
Language Comparisons
Actually based on metrics we have gathered from several large Smalltalk projects and reviewed with Capers Jones, the productivity numbers Jones cites are probably too conservative for Smalltalk. We found that the tables Jones provides in his seminal book on "Estimating Software Costs" ISBN 0-07-913094-1,on predicting how long a software project will take, match very closely with actual results. The book takes into account a number of variables in terms of software project type, (i.e. business software vs operating system), team skill as well as lowest cost or quickest delivery. The models are based on SPR's database of thousands of projects.
Since the models Jones provides predict project man hours fairly accurately when compared with actual results, we can then use the models to test various "what if" sceanrios including differences in programming languages. The models that Jones presents seem to show that typical Smalltalk productivity is about 6x that of typical Java productivity for the same type of large project. If one is working on a small project, then the differences in programming technology don't matter because the inertia of getting going, technology set up and debugging are much more of the total project time.
We have presented our results at several conferences with good feedback from the audience about their veracity. One other point is that, as of a few months ago, all of the data regarding Java productivity from the SPR language comparison, appears to be unchanged from several years ago.
Ed Klimas
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