It also monitors its own work to provide a qualitative measure. In the case of Kellogg, a separate team of agents called randomly selected customers and in the most recent survey, more than 72% said they were 'very satisfied' with the quality of service.
The agency's effectiveness is demonstrated by its careline support for Britvic. An independent survey this year ranked it best in the industry out of 25 blue-chip companies.
CPM is well ahead in the multilingual arena. Earlier this year it opened a contact centre in Barcelona, adding to its facilities in Holland, France, South Africa and Australia. This helps meet the growing demand for international campaigns that fit national customs and needs.
Last year's winner, MM Teleperformance, has rebranded from MM Group, having been acquired in May by SR Teleperformance, the world's second-biggest outsourced contact centre provider. It has now been merged with BPS Teleperformance in Birmingham, giving it a total of eight networked sites nationwide and more than 2200 staff.
The merger is the latest stage of chairman Jeff Smith's drive to make the company a market leader. This is combined with organic growth of £5m this year that takes its turnover to £56m, which could raise it one place to third in next year's league table.
The company continues to expand its public sector work, and has just been entrusted with a highly sensitive project by a government agency. This has meant expanding its centre in Bangor in Northern Ireland to take account of stringent security needs, creating an extra 200 jobs.
A reputation for good work for charities and membership organisations has led to Pell & Bales retaining longstanding clients such as the Labour Party and WWF.
However, it has moved decisively to extend its sphere of operations, making a successful bid for telecoms and business-to-business contracts, winning £2m of work from RAC, Tele2, PriceLess, Consodata and others.
The agency grew its earnings by 21% in 2003 and expects to increase by 25% this year as part of a three-year aggressive business growth plan. A second London site has just been created with 50 seats and a fourth site will open next summer, possibly in the North of England or South Wales.
Other wins for Pell & Bales include The National Trust, RSPB, Macmillan Cancer Relief and the British Heart Foundation, while incremental activity has risen by 16%.
Its dedication to charity work has not been forgotten. The agency has been involved in a pioneering project to identify potential donors on the internet, aimed at reaching younger individuals with a higher disposable income who are willing to campaign as well as make donations.
Initial results have been encouraging, with an average 11.5% of contacts agreeing to provide support of more than £76 a year. This benefits charities including Amnesty International, the Red Cross and the NSPCC.
An 11% growth on its £23m turnover and 10 new business wins made 2004 a good year for Inkfish. As well as adding American Express, Sainsbury's and MFI to its client list, it has increased business from existing clients such as British Airways, providing pre-sales advice, sales and customer care to its holiday division.
Agencies that carry out research arguably add to the industry's long-term effectiveness. One doing just that is Prolog Connect, which proved that matching agent-caller profiles creates greater empathy with customers, helping to bring quicker call resolutions and raise customer satisfaction.
Calls where customer and agent were of similar age are the most successful, the agency's survey found. Nearly 60% of calls with an age gap of less than six years were rated as good, while those that showed a large age gap were the least satisfactory.
The work underscored the importance of agents being aware of callers' circumstances and of using the right verbal cues to gain their trust. Use of humour was also valued, appearing in 50% of all calls rated as excellent, but in only 27% of unsuccessful ones.