title: Practice parameters and strength of recommendation data: a variable compass.
abstract: BACKGROUND
  Practice parameters and guidelines shape and influence the method and manner in which medicine is practiced. With more than 121 scales and methods of assessing and rating evidence, a comparison of practice parameters can appear daunting. An evaluation of the evidence engenders a sense of the evolution of a specialty and a roadmap for the future.
  
  
  OBJECTIVE
  To assess the level of evidence underlying recommendations in allergy-immunology (AI) practice parameters.
  
  
  METHODS
  We analyzed the practice parameters that guide AI (n = 15), otolaryngology (n = 8), pediatrics (n = 13), and internal medicine (n = 10) as they appeared on August 30, 2012. Strength of recommendation data was compared after making adjustments for differences in rating scales.
  
  
  RESULTS
  The strength of recommendation calculated from strong to weak for the AI practice parameters using a standardized format yielded the following grades: A in 195 (13.9%), B in 342 (24.4%), C in 606 (43.2%), D in 231 (16.4%), and E in 29 (2.1%). Controlled trial-based evidence (A and B) demonstrated considerable variability among individual AI practice parameters (range, 1.3%-100%). Evidence from controlled trials was lower in the subspecialty fields (38.3% in AI and 38.2% in otolaryngology) compared with the primary care fields (55.6% in pediatrics and 86.1% in internal medicine).
  
  
  CONCLUSIONS
  Considerable variability exists in the strength of recommendations within the AI practice parameters. The guidelines created by the primary care fields rest on a larger base of evidence collected from controlled trials. These findings likely reflect the adopted approach of making recommendations for less well-studied conditions and practices in AI to assist practitioners and patients and at the same time highlight the myriad opportunities for future research.
authors.affiliation: Division of Allergy-Immunology, Walter Reed National Military Medical Center, Bethesda, Maryland. Electronic address: taylor.a.banks@health.mil.
authors.forename: Taylor
authors.initials: T
authors.lastname: Banks
authors.affiliation: Division of Allergy-Immunology, Walter Reed National Military Medical Center, Bethesda, Maryland.
authors.forename: Julia
authors.initials: J
authors.lastname: Savitz
authors.affiliation: Division of Allergy-Immunology, Walter Reed National Military Medical Center, Bethesda, Maryland.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Nelson
mesh_terms: D000486:Allergy and Immunology / Q000592:standards*; D019317:Evidence-Based Medicine / Q000592:standards*; D006801:Humans; D007158:Immunologic Techniques; D007388:Internal Medicine / Q000592:standards; D010036:Otolaryngology; D010372:Pediatrics; D017410:Practice Guidelines as Topic