title: [Mastered with statistics: perfect eye drops and ideal screening test : Possibilities and limits of statistical methods for glaucoma].
abstract: BACKGROUND
  The use and the understanding of statistics are very important for biomedical research and for the clinical practice. This is particularly true for estimation of the possibilities for different diagnostic and therapy options in the field of glaucoma. The apparent complexity and contraintuitiveness of statistics along with a cautious acceptance by many physicians, might be the cause of conscious and unconscious manipulation with data representation and interpretation.
  
  
  OBJECTIVE
  Comprehendable clarification of some typical errors in the handling of medical statistical data.
  
  
  METHODS
  Using two hypothetical examples from glaucoma diagnostics the presentation of the effect of a hypotensive drug and interpretation of the results of a diagnostic test and typical statistical applications and sources of error are analyzed in detail and discussed.
  
  
  RESULTS
  Mechanisms of data manipulation and incorrect data interpretation are elucidated. Typical sources of error in the statistical analysis and data presentation are explained.
  
  
  CONCLUSIONS
  The practical examples analyzed demonstrate the need to understand the basics of statistics and to be able to apply them correctly. The lack of basic knowledge or half-knowledge in medical statistics can lead to misunderstandings, confusion and wrong decisions in medical research and also in clinical practice.
authors.affiliation: Fachbereich Medizintechnik und Technomathematik, Fachhochschule Aachen, Campus Jülich, Heinrich-Mussmann-Str. 1, 52428, Jülich, Deutschland. kotliar@fh-aachen.de.
authors.forename: K E
authors.initials: KE
authors.lastname: Kotliar
authors.affiliation: Augenklinik, Klinikum rechts der Isar, Technische Universität München, 80333, München, Deutschland.
authors.forename: I M
authors.initials: IM
authors.lastname: Lanzl
mesh_terms: D003198:Computer Simulation; D003627:Data Interpretation, Statistical; D003951:Diagnostic Errors / Q000517:prevention & control* / Q000706:statistics & numerical data; D003941:Diagnostic Techniques, Ophthalmological; D006801:Humans; D008403:Mass Screening / Q000379:methods*; D015233:Models, Statistical; D009883:Ophthalmic Solutions; D017063:Outcome Assessment, Health Care / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D009883:Ophthalmic Solutions
keywords: Median; Prevalence; Sensitivity; Specificity; Statistical data interpretation