The Old and New Statistical Accounts were written by ministers of the parishes in Scotland.  The First or Old Statistical Account was suggested by Sir John Sinclair, MP for Caithness (1754-1835).  He was a lay member of the General Assembly of the Church of Scotland and was very interested in agricultural improvements.  Sets of questions were sent out to every minister, 160 in number, and the idea was to gather information, and the questions covered topics like on natural history, topography, climate, population, agriculture, industry and miscellaneous matters.  This work covered the years 1791 to 1799.  Some ministers wrote enthusiastically about their pet subjects, some wrote very little about anything. 

Previous attempts had been made by the Church of Scotland to gain similar information had generally failed, though a survey was done by the ministers for Rev. Alexander Webster, who created a population census of Scotland in 1755.

The New Statistical Account was also mainly written by parish ministers, though accounts were also included in some reports by  doctors, landowners, schoolmasters.  It covers the years 1834-1845.

For further information on the making of the Accounts see:

http://edina.ac.uk/stat-acc-scot/reading/intro.shtml