Turnover data is provided by The Data City based on financial reporting to Companies House. Because there can be a lag in financial reporting, The Data City uses modelling to estimate current-year values where direct data is not yet available. Where this is not possible, no data is reported. It is important to note that turnover figures should be treated with care: some agency types, particularly media agencies, may include media billings and other campaign costs in the turnover figure submitted to Companies House.