it is better to speak with the person who will get your candidates in front of the decision maker, keep you informed, and make sure you get paid. That can be any of the people you listed... HR or a C-level exec can get you in the door (and make sure you get paid) but if you irritate the hiring managers by going over their heads or thinking they're not important you are doomed. Same for HR, actually. I guess that's kind of a non-answer but it really depends on the company.
Hi Ricardo, my suggestion would be to talk to the one in "pain". If the Hiring Manager is getting frustrated that he is not getting the right candidates, he is the best one to approach. Similarly, if there is a centralized HR and he / she is getting frustrated that he / she has 10 hiring managers and she/he needs help, then that is your best contact point. When I was doing IT contracting some 8-10 years ago, I discovered a higher success rate approaching Hiring Managers than the HR. HOWEVER, (and this is a very important one) I had several HR Managers who were also excellent clients and they accounted for more repeat business than the IT Managers. As Amy said, depends on the company, but NEVER go in without doing some preliminary research. All the best!
Hi Ricardo, Amy and Rita have provided some great advice ... I usually like to work with the Hiring Sponsor Like Ritu, first and work backwards... Sometimes the "I was doing some research on your company and would love to meet with you for a quick coffee to learn more about your needs works .." That can lead to: Sure let's meet.., " or "Do you handle Data Warehousing requirements ..." or "Talk to Jane Doe in HR tell her I sent you ..." or still not the worse response "Call me back in a month ..." The key here is you are not asking for a Requirement you are asking to learn more about the Company in order to be successful for when you do get a requirement ... Hiring Authorities like that across the levels described in your post... Then add the "persistence, stay with it" ingredient and you're on your way....
It may depend on the ty pe of roles you focus on. I've found that an initial contact to a C level person works best for me. I'm usually referred to HR but when the referral comes from the executive it seems to be more effective and the HR person then calls me with a search or two. When I used to do administrative recruiting it was more effective to call HR first. It really just depends. Either way though, once I'm in, I work however they prefer it. HR can be a great partner.