Which of the following factors does NOT affect how the premium is determined?

When determining insurance premiums, various factors come into play that directly influence the cost. Claims cost is a significant factor because it reflects the amount the insurer expects to pay for claims. Higher expected claims costs typically lead to higher premiums. Similarly, operating expenses, such as administrative costs and overhead, are essential for calculating premiums since these costs ensure the insurer can cover its day-to-day operations while remaining solvent.

Investment earnings are also a critical factor because they represent the income insurers generate from investing the premiums they collect. High investment returns can allow insurers to reduce premiums, as they have additional revenue sources to offset claims and costs.

On the other hand, an employee's age is not a direct factor in the general calculation of insurance premiums for all types of insurance. While age can influence specific products, such as life or health insurance, in general commercial insurance contexts it does not significantly impact the overall premium determination. Therefore, this option stands out as not directly affecting premium calculations like the other factors do.