Market rate is based on the responsibilities of the job, not on what a single candidate might want. My advice is to not try to negotiate down on what you're going to offer a candidate, just state the responsibilities of the job, the expected compensation, and let the best match fill that. This isn't a menial job where you can swap in a new employee quickly, but is a major investment where an extra 5-10% could save you a large amount of wasted effort when this person moves on to the next company using his time at your company to close that wage gap you created. It always amazed me that companies would fight over a relatively small amount, lowering retention rates, while paying massive amounts towards recruiting and training of new employees.
Market rate is based on probability of finding candidate to accept the lowest possible rate. It does not really depends on responsibilities.
A person can double the salary for the same responsibilities simply moving to the other company/location.
And yes, company will easily accept higher attrition than increase salary by 10%. Now even more so, and will hire for lower salary because there are so many desperate unemployed people who have no choice but to accept huge pay cut.
