Activity rate conventions

The excluding-leave activity rate is the share of consultants' time that gets billed. Take billed days and divide them by potential working days minus leave: paid vacation and the statutory rest days that come with reduced-working-time agreements. The result is the rate most IT-services firms use to steer billable utilization month to month.

The including-leave rate keeps the same numerator but leaves vacation and reduced-working-time days in the denominator, so it is always less than or equal to the excluding-leave rate for the same person. Neither convention is defined by law or by the Syntec labour convention (IDCC 1486); both come from management practice, which still disagrees on whether sick leave is also excluded.

Two managers can report different activity rates for the same consultant because only the leave treatment differs: the holiday calendar swings one denominator and not the other, which is why the two numbers diverge. The excluding-leave rate flatters month-to-month steering by discounting planned absence; the including-leave rate shows how much of total capacity actually bills. Neither rate is defined in law, and firms even disagree on sick leave, so two teams comparing numbers without a stated rule risk a silent mismatch. Stating the convention and showing both figures keeps steering honest.