In line with common practice in the archive sector, the CMS archives are subject to a period of closure before being available for research or consultation.

Thirty years was the period decided by the directors of the Society in consultation with the archivist. This covers the majority of the material with some exceptions.

Unlike the closure period applied to large archives (eg The National Archives), this is to be administered by decade rather than on an annual basis. Therefore material for any given decade will only be available at the end of that decade plus 30 years (eg material for the 1990s will be available for research in 2029.

Promotional material

(No restriction)

This category includes publications sent to members and supporters (ie Prayerlines, The Call) and flyers distributed to promote the work of CMS (including events, appeals etc).

Correspondence, minute books and material generated in the course of business

(30 years by decade)

This category comprises the bulk of material in the archive and will be generated from every department and function within CMS. Material will be transferred to the archivist when it ceases to have currency as a part of the everyday business of CMS (but can still be recalled by the originating department prior to its transfer as official archives to the University of Birmingham). There are two important exception to this, listed below.

Link letters/Annual letters

(50 years by decade)

These are the letters sent by Mission Partners to their supporting churches and friends. These will generally be available for research after 50 years, but may be subject to longer retention if they are of a particularly sensitive nature.

Mission personnel files

(115 years from birth of individual)

These are the files kept on individual missionaries since 1934. They contain personal information as well as details of furloughs, deputations and often pension arrangements and contributions.

There is a strict rule that these files cannot be seen by anyone outside CMS until a period of at least 115 years have passed since the individuals birth. They can only be seen within CMS by a person with a genuine reason (eg Pension, HR, Personnel).

To date no personnel files have been made available for research.