|Mobile networks call success rate surveys - May 2003|
Consumers take a number of factors into account when buying a mobile phone. The ability to make a successful call is one such factor. Four mobile network operators - O2, Orange, T-Mobile and Vodafone - have worked with Oftel and consumer groups to produce survey information on call success rates.
The results show the successful call rate that each of the four network operators either reached or bettered - both at the national level and in each region. The results quoted are not necessarily for the same operator.
The results of earlier rounds of surveys can be found here:
For further information contact Chris Smithers: tel 020 7634 8876 or email
Reference to "call success rates" refers to the test equipment’s ability to set up and hold a call for two minutes. This measure does not give a figure for the audio quality of the call.
The operators are carrying out their own drive-round surveys making test calls on the basis of a common survey specification. The survey methodology used and the results have been independently audited.
Each operator made at least 20,000 test calls over the six month period. Seventy cities and towns and major A-roads and motorways were tested throughout the UK.
Measurements were made using an agreed set of routes although the same routes were not necessarily driven in the towns and cities. The roads were driven Monday to Friday between the hours of 8 am and 8 pm, excluding Bank Holidays.
In order to cover a wide range of locations, data was compiled using vehicles with roof-mounted aerials and automatic call generation equipment to make test calls. The drivers of the vehicles did not make calls.
Customers should note that the survey results are limited by a number of factors, including the nature and location of the tests employed and the testing equipment used. Consumers’ own experience may differ from the reported level of service depending on factors such as the handset and equipment being used, geographic location and time of day.
Furthermore, when making a purchase decision, consumers should also take into account other factors including price of handset, connection charge, call tariffs, claimed coverage, service features, terms and conditions and indeed any other factors which individuals consider relevant to their needs.
Calls were made to and from mobiles connected to the automatic call generating equipment and dedicated fixed test lines: mobile to fixed telephone line and fixed telephone line to mobile, in the ratio of 2:1.
Calls were regarded as successful if held for two minutes.
The figures quoted only reflect the service experienced on the specified routes, at the time of day that the calls were made and the type of handset used.
Mobile network operators use different test equipment and different signal frequencies and so adjustments have been made to try to compensate for these differences.
Vodafone and O2 have deployed the use of EGSM which may improve network performance (if the customers have the latest handset to explore this feature). However, Vodafone alone tested this new capability for the first time in the assessment of network quality for the period April 2002 - September 2002.
The results of the surveys have been independently audited. Each operator’s figures are statistically valid at the national level to approximately + or – 0.5% at a 95% confidence interval. As recommended by the auditor, the results have been rounded to one decimal place.
The operators, together with Oftel and consumer groups, are currently working to extend the surveys to cover other aspects of quality.
Consumers wanting further information about the survey should contact the mobile phone network operators directly.
As indicated above, although the results have been independently audited, the survey was carried out by the four mobile network operators according to their own agreed criteria. Therefore Oftel accepts no liability in respect of any of the results.