It is important to ensure that different copies or versions of files, files held in different formats or locations, and information that is cross-referenced between files are all subject to version control.

It can be difficult to locate a correct version or to know how versions differ after some time has elapsed. A version control strategy depends on whether files are used by single or multiple users, in one or multiple locations and whether or not versions across users or locations need to be synchronised or not.

It is important to keep track of master versions of files, for example the latest iteration, especially where data files are shared between people or locations, e.g. on both a PC and a laptop. Checks and procedures may also need to be put in place to make sure that if the information in one file is altered, the related information in other files is also updated.

Best practice is to:

• decide how many versions of a file to keep, which versions to keep, for how long and how to organise versions
• identify milestone versions of files to keep
• uniquely identify files using a systematic naming convention
• record version and status of a file, e.g. draft, interim, final, internal
• record what changes are made to a file when a new version is created
• record relationships between items where needed, e.g. relationship between code and the data file it is run against; between data file and related documentation or metadata; or between multiple files
• track the location of files if they are stored in a variety of locations
• regularly synchronise files in different locations, e.g. using MS SyncToy software
• maintain single master files in a suitable file format to avoid version control problems associated with multiple working versions of files being developed in parallel
• identify a single location for the storage of milestone and master versions of files

Examples of file versions

• date recorded in the file name or embedded within the file
  HealthTest_06-04- 2008
• version numbering in the file name (v1, v2, v3 or 00.01, 01.00)
  BGHSurveyProcedures_00_04
• version description in the file name or embedded within the file (draft, final)
  FoodInterview_1_draft
  FoodInterview_1_final
• a file history, version control table, or notes included within a file in which the versions, dates, authors and details of changes to the file are recorded

Version control can also be maintained through:

• version control facilities within software used
• using versioning software, e.g. Subversion (SVN)
• using file sharing services such as Dropbox, Google Docs or Amazon S3
• controlling rights to file editing
• manual merging of entries or edits by multiple users

VIEW AN EXERCISE ON HOW TO APPLY VERSIONING IN MS WORD

VIEW AN EXERCISE ON HOW TO SYNCHRONISE FOLDERS

Authenticity of data

Because digital information can be copied or altered so easily, it is important to be able to demonstrate the authenticity of data and to be able to prevent unauthorised access to data that may potentially lead to unauthorised changes.

Best practice to ensure authenticity is to:

• keep a single master file of data
• assign responsibility for master files to a single project team member
• regulate write access to master versions of data files
• record all changes to master files
• maintain old master files in case later ones contain errors
• archive copies of master files at regular intervals
• develop a formal procedure for the destruction of master files