Dear Mr _____ :
Thank you for your kind invitation to speak at your upcoming event. As you are aware, I have been doing some work on that topic and have some insights to share.
As I am sure you also know, I recently approached your organisation with an application for funded work. That application was rejected.
Given that both notices — the rejection and the invitation — arrived in the same week, I believe you might be unaware of my situation. I would therefore like to explain it.
I am a researcher-for-hire. I work on externally funded projects, and I am responsible for obtaining funding as well as conducting the research. My current employer, as well as my former employer, have made it clear that my employment is contingent on my maintaining a stream of funding. My job is only as secure as the next research contract.
As a result, I need to be mindful of paid work versus unpaid work. A certain amount of unpaid work is unavoidable. In addition to writing proposals, I contribute to the profession, promote the use of economics tools to the wider public, meet people and discuss their research needs, and more. These activities are unfunded. I am not paid for them. There is no underpinning funding, no contribution-to-the-research-environment account, no payments just because.
I am paid by the piece. It is all milestones and deliverables. When I deliver, I can bill; when I bill, I keep my job. It is simple and brutal, but it is the life of a researcher-for-hire. I would say my position is unusual, but as I look around at my peers and the next generation of workers — the freelancers, adjuncts, temps, and consultants — I see that it is rather common.
You might not see it from your perspective as a secure, permanent, salaried employee, but your invitation is a request to work for free. I am afraid, therefore, that I must decline.