- all firms are different. Okay, maybe a bit of hyperbole, but there are a variety of models that can be applied, which make comparisons difficult.
- assets under management may be a good gauge to say how much you can afford but not necessarily how big you should be.
- number of accounts: the more you have, the larger your staff has to be
- reliance on spreadsheets: the greater the reliance, the greater the amount of manual effort and therefore the greater need for staff. Packaged software typically has many tools that aid the team, thus reducing the manual effort.
- activities of the group: performance measurement can address returns (portfolio and subportfolio), risk, attribution (equity, fixed income, balanced, etc.), and the Global Investment Performance Standards (GIPS(R)). If the firm is only engaged in returns, their staffing needs won't be too great; but, if they take on more tasks, more staff may be needed
- reporting: if the group handles both internal and client reporting, staff is needed; also, if there are custom reports or if the frequency varies from daily to monthly to quarterly, more staff may be needed
- reliance on and support from back office operations: if the operations staff is clued into the needs of performance, they may be helpful in addressing data issues; but, if they are clueless (okay, a bit strong, but you get the point) about their needs, they may not be as helpful as one might hope, meaning more work falls to the performance measurement team.
- client demands: if the firm caters to a lot of individual needs, including custom reporting or fielding inquiries, the workload increases, meaning the need for staff.
The answer to the amount of staff one needs is hardly a simple one. Hopefully this at least gives you some ideas.