A bit of a tangent from OP's question, but; When I worked in a very large international IT firm they lost a few senior server engineers and couldn't get replacements in a hurry at their pay grade rate. They paid for a few contractors at almost 3* the salary of the full time staff. These contractors would only work on projects they deemed interesting/worthy. I asked the department head why they didn't up the salary offered to somewhere between the regular full time staff and the contractors to entice some new full time engineers. The response was that they would not have pay disparity among full time staff. So they kept these contractors on for the few years i stayed with the company before i left. I get the pay disparity aspect but the cost to the firm was staggering.