Most software testing services also provide software development services and some even provide more general business process outsourcing services. When you see this situation, you’ll frequently find that software developers sell at a higher price and provide much more profit than software testers. So, it makes sense that the company that provides the software testing services will optimize their better talent to the higher priced role of software developer than the lower priced role of software tester. So, when you ask for a tester, the odds are that you will get someone who just wasn’t quite good enough to be a software developer.
There is a misconception that software testing services are a commodity – it’s just testing, right? Software testing may be a commodity for everyone else, but when it comes to your software, I doubt you want the cheapest general solution out there. You didn’t use that approach when you built your software, so I doubt you’ll want to use the cheapest testers you can find.
And since the testers are low margin and low paid, they tend to want to improve their situation and move up their career ladder. The testers didn’t start as testers, they wanted to be developers. The minute they get a better opportunity, they will take it and leave your project. This almost never happens at a “good” time.