The acceptance criterion 'The annual increase to be less than half the rate of inflation' is precise and measurable, providing a clear standard against which the running cost of the outsourced service can be evaluated. This ensures predictability and control over cost increases. By contrast, options like 'Must be kept to a minimum,' 'Must be kept to a level acceptable to the Ministry of Food Hygiene,' and 'Subject to market conditions' are either too vague or dependent on external factors, making them difficult to measure and enforce effectively.