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. Author manuscript; available in PMC: 2013 Nov 1.
Published in final edited form as: J Am Coll Surg. 2012 Jul 21;215(5):722–730. doi: 10.1016/j.jamcollsurg.2012.06.018

Table 4.

Attributes needed for assessing external validity or generalizability

Attribute N(%) Dossiers
N intervention centers
   N centers not reported 24/290 (8.3)
   Single center 133/266 (50.0)
   Multi-site 133/266 (50.0)
     Median number of centers (range) 12 (2–217)
     2–5 centers 40/133 (30.1)
     6–10 23/133 (17.3)
     >10 70/133 (52.6)
Eligibility criteria for inclusion of intervention centers (multi-center trials only)
   Not reported 117/133 (88.0)
   Inclusion criteria described 16/133 (12.0)
N surgeons/interventionists
   N interventionists not reported 225/290 (77.6)
   N interventionists reported 65/290 (22.4)
   Single interventionist 31/65 (47.7)
   Multiple interventionists 34/65 (52.3)
     Median number interventionists (range) 3.5 (2–66)
     2–5 interventionists 21/34 (61.8)
     6–10 7/34 (20.6)
     >10 6/34 (17.6)
Eligibility criteria for inclusion of interventionists (multi-interventionist trials only)
   Not reported 20/34 (58.8)
   Inclusion criteria described 14/34 (41.2)
Pre-trial standardization of operative technique (multi-interventionist trials only)
   Not reported 26/34 (76.5)
   Described critical elements of technique 8/34 (23.5)
Assessment of interventionist fidelity to standardized operative technique (multi-interventionist trials only)
   Not reported 31/34 (91.2)
   Assessment method described 3/34 (8.8)
Sponsor role in conduct of trial (Out of trials reporting commercial sponsorship only)
   Trial design 26/89 (29.2)
   Data analysis 31/89 (34.8)
   Preparation of manuscript 29/89 (32.6)
Size of trial
   Median number of trial participants (range) 121.5 (30–3,120)
   30 participants 4/290 (1.4)
   31–60 56/290 (19.3)
   61–100 59/290 (20.3)
   101–200 63/290 (21.7)
   >200 108/290 (37.2)