Archive for September 2nd, 2010
Well now here’s an odd thing. In an otherwise frankly insulting article supposedly about visa fraud our old friend Don Burleson refers to Oracle Corporations salary survey for Oracle professionals which apparently shows US DBAs earning $97k on average whilst DBA staff in the rest of the world were close to about half of that salary. In a global economy this seems more than a little unlikely. However there are some pretty good reasons to take the salary survey with more than a little salt. As any graduate of a mathematical discipline (including computer science and the like) ought to know drawing statistical conclusions from survey data is notoriously difficult since the sample sizes tend to be small and the population non random. In this case as well it’s a cause for some concern that the source of the survey is a company looking to promote its own training.
In this case Oracle don’t publish the raw survey data – which is a shame – and they quote different figures for the responses to the survey which isn’t encouraging. On the front page we see
The survey was open to all Oracle Certified Associates (OCA), Professionals (OCPs), Masters (OCMs) and Experts (OCEs) worldwide as well as those not currently certified. This salary survey features data compiled from 2,655 respondents in more than 60 countries.
Whereas on the salary by region page we see
We had respondents from over 95 countries worldwide
This immediately suggests to us that the sample size could be quite small for a number of nations (on average taking the smaller number that’s 44 respondents per country, taking the figure of 95 its 27). It is of course likely that the figures for the US, UK, India, Germany,Japan etc may be quite large with other countries poorly represented. because Oracle don’t publish the data set we don’t know.
In addition there are some quite interesting breakdowns on the Oracle Website. In EMEA for example just 31% of respondents work for companies that employ more than 5,000 people, in the US that figure is over 50%. It’s not unreasonable to suppose that candidates who work at larger organisations with more employees, more databases and more money likely earn larger salaries than those who work at smaller ones.
Similarly there’s an oddity in the EMEA figures regarding experience where we are expected to believe that on starting out (0-2 years) an administrator can expect a salary of $43k, but after that first job move, obtaining certifications and showing their aptitude (3-4 years) the salary average drops to just $34k.
These sorts of oddities make me rather suspicious of the pretty graphs on the Oracle education site, but probably the killer for me is the fact that (like other governments around the world) the US Govt maintains statistics on employment. You can find these at http://www.bls.gov/oes/current/oes_nat.htm#15-0000 where we have a nice category for Database Administrators and an estimated mean salary of $75k. The breakdown of these figures is almost certainly publicly available.