The Lawyer UK 100 Annual Report is based initially on responses to questionnaires sent to firms in July. A team from The Lawyer, led by features editor Matt Byrne, followed this up with interviews, usually with the managing partner, head of departments or finance director. An increasingly small number of firms declined to give any information. Figures were estimated for these based on conversations with partners, former partners, consultants, recruiters and other industry insiders. Given that many spoke off the record, we do not identify those firms that cooperated officially with the research and those that did not.

All figures, including profits, turnover and headcounts, are taken from the end of a firm's financial year. All lawyer and partner numbers were provided by the firm, whether or not they officially cooperated on the financials. We have published two fee-earner figures (one including trainees, paralegals and consultants and the other without) to give another indication of the type of practice. High leverage ratios (ie equity partner to fee-earner) or high numbers of paralegals could indicate bulk work such as conveyancing or debt recovery. The leverage ratio is the number of assistants divided by the number of equity, not total, partners.

We also asked firms for financial management information covering a range of issues including work in progress (WIP) and debtor days, the percentage breakdown of a firm's major practice areas (to give an indication of why WIP might be long or short), equity partner capital contributions and debt. We also analysed lockup targets wherever possible, while the `achieved' figure relates to the sum of average WIP and debtor days across all departments at year-end.

With The Bar Top 30 we are also publishing a comprehensive analysis of a set's financial health. The key indicators of gross income and chambers contributions (the percentage of income each tenant is charged to cover clerking, property and administration costs) taken as at the end of the last financial year remain. We have also included staff to barrister ratios and the number of appearances in the Court of Appeal and House of Lords. An increasingly small number of sets declined to disclose financial information. Their figures are estimated based on conversations with tenants, clerks and former tenants.