As a professional in this field, top reasons would be...
Dissatisfaction with pay
Limited/No career progression
Dissatisfaction with environment/culture
Dissatisfaction with management
Poor work-life balance
Poor job design/expectations of role
Poor taining quality/knowledge management
Inadequate tools/systems
Edit: I should also point out we have about half a dozen ping-pong tables scattered around my work and our turnover figures were bang on average for annual benchmarking against the sector. I consider the average too high, though, and will be targeting better retention over this year. We'll need at least double the amount of ping-pong tables.
But I have no money and lemons are expensive! If only there was a way we could acquire lemons without paying for them... Anyone know where I could find a lemon tree?
Very correct. You can solve bad culture by throwing more money at the problem. Preferably all at once with zero maintenance budget or governance so that the amenities in question can become non-functional monuments to your superior culture. Future generations will find these and marvel at your ingenuity from the safety of the water cooler.
Strategic Workforce Planning. It's a bit different to HR in that there's a lot of data analysis. Typically we would use data to identify retention issues (reasons, areas, seasonality, etc) and figure out how to improve it. We'd then hand that over to HR to implement fuck up.
There’s some new research that shows raising pay is not great for retention. Studies say it’s better to take that money and put it into a long-term benefit line a pension, profit sharing, while life insurance with a cash out value, etc.