On receiving an MSc at Reading University, Keith started his career as a statistician in 1972 in the Population Studies Section of the Greater London Council. Whilst at LAMSAC and MVA Systematica he managed the SASPAC 1981 census analysis software (which won the British Computer Society Social Benefit Award) and data products including the ED-LINE 1991 census digital boundaries (which won the Association for Geographical Information Industry Award). He also worked for the American market analysis company CACI for two spells, firstly setting up its Public Services Group, and latterly as Director of its Financial Services Group.

Keith then set up Demographic Decisions in 1996 to provide impartial consultancy advice to users of demographic data, and has carried out many projects for both commercial and public service clients in the last decade.
In 1998, he also established the Demographics User Group (DUG), which represents to government the interests of several large commercial users of public data – more details are given at DUG.

In addition to the day jobs, Keith is an active member of several professional organisations, author of many papers and articles, and a frequent speaker at conferences.