Grading of evidence

Publication Date: 
June 17, 2016

Selected recommendations in these Guidelines have been graded using adaptation of some components of the GRADE scoring system,[1] with the addition of two additional domains to describe details of the research which underlies the recommendation, as well as the population(s) in which such research was conducted. Each graded recommendation will include mention of the population(s) in which research was conducted (transgender (T), non-transgender (NT), or both (T/NT) (Table 1); an indication of, among all sources informing that particular recommendation , the strongest form of underlying evidence (meta-analyses, randomized trials, observational studies, expert opinion) (Table 2). Lastly, an overall grading of the strength of recommendation is made (strong, moderate, weak) which is based on the above criteria as well as strength of the consensus recommendation as determined by expert opinion interpretation of available data (Table 3.).

Key recommendations are listed in bold. Some recommendations are not graded as they are based on existing recommendations from other professional organizations.

Grading of evidence

Table 1. Populations in which data exists to inform a particular recommendation
Description Code
At least some data in transgender population T
No data in transgender population, but data from other populations NT
No data (expert opinion only) X
Table 2. Strongest available data to inform a particular recommendation
Description Code
Meta-analysis M
Randomized controlled studies R
Observational studies O
Consensus expert opinion C
Table 3. Overall strength of recommendation, taking into consideration the above as well as expert interpretation of available data in context
Description Code
Strong S
Medium M
Weak W


  1. Guyatt GH, Oxman AD, Vist GE, Kunz R, Falck-Ytter Y, Alonso-Coello P, et al. GRADE: an emerging consensus on rating quality of evidence and strength of recommendations. BMJ. 2008 Apr 26;336(7650):924-6.

Medical Referral Disclaimer

The CoE is unable to respond to individual patient requests for medical guidance. If you need medical advice, please contact your local primary care provider. If you need clarification, seek a second opinion locally or have your provider contact us for more information.