Current Availability of Perl, Php, Python and Ruby Programmers
Companies choose a programming language for many reasons, but one of the top ones would be the availability of developers in that language. You don't want to start a development project with a language and realize that there are only a handful of people out there, who know that language.
How do we estimate the number of programmers experienced in each language?.
Rather than absolute numbers, it would be sufficient to compare the relative numbers of developers experienced in a particular language from a large sample of developers. This ratio estimate will more or less hold good in the general population.
To get an unbiased, large sample, we turned to the top 3 search engines, Google, Yahoo and MSN to find the number of resumes on the web with a particular skill. The hypothesis is that the likelihood that a Perl programmer will put his/her resume online is the same as that of a Php programmer, so on and so forth.
The query we used to find resumes is
(intitle:resume OR inurl:resume) LanguageName -intitle:jobs -resumes -apply
in the three search engines.
Observations: In Google Php results are about 6 times more than the next skill, Perl. Where as in Yahoo the results between Php and Perl were nearly similar. MSN showed Php to be 5 times that of Perl. What this tells us is that there is a large variation between the relative number of resumes for each skill in each search engine.
Resumes in Search Engines
As seen above, there is a wide variation in the raw numbers from each of the search engines. We need a normalized set of numbers that can say that for every 100 php programmers, there are 40 Perl programmer, 20 Python and 10 Ruby programmers, or something like that.
The first thing we did is to normalize the skills in each search engine. Then we assumed the relative market share of the search engine (totally arbitrary, needed a weighting factor of the search engines) and computed relative numbers. The relative market share of Google vs Yahoo vs MSN is about 44:29:13. To those, who have a keen eye, the market share of the three search engines come only to 86 and not 100. We scaled the search engine weighting numbers so that we had 100.
Resumes in Search Engine - Normalized
Conclusion: The combined search engine column estimates that for every 100 PHP developers, there are 42 Perl developers, there are 12 Python developers and 4 Ruby developers.