The description of the methodology states that subscribers known to be under 18 were excluded from the analysis, leading to a set of related concerns. processing; necessary from the point of view of the mobile provider, but problematic for any attempt to generate census-type data. There is no way to link a given phone record to an individual, and thus to individual and household level characteristics. The ability to link is central to the richness of census outputs. Without individual level data it is hard to filter out data that are not required. In the case of journey to work data, that would include persons aged under 16. Whilst this information might be known for some people, it will not be robust: it is not uncommon for young people to have a phone for which the contract is in a parent’s name.
Over-collection of data may be another problem spain rcs data perhaps; one 2016 report states (without giving a source) that 14m people in the UK carry two mobile phones. This is likely to be a non-random sample of people, and would potentially distort results. Even if there were clear records of phone ownership, it seems legally and practically unfeasible to link phone records to any other record level data and data modelling would be required.
In census data the home location, workplace location and method of travel to work are all explicitly recorded, as are characteristics of the job and of the workplace. With phone data, home location and workplace location are determined from the data, and any other characteristics have to be estimated. At best the phone workplace location might be estimated to a sufficient level of accuracy that a reasonable assumption can be made about the specific employer, but details of the job itself would remain unknown.