Common Ommissions and Errors in Published Papers

Rushton provides a report on some of the most serious omissions and errors in papers presented in recent years to the journal, ‘Occupational and Environmental Medicine’. These are:

Design

• Authors unclear about type of epidemiological study;
  
• Adequacy of sample size not considered;
  
• Bias in selection of subjects; Execution
  
• Data collection problems and missing data not adequately reported;
  
• Non-respondents not investigated;
  
• Sample selection and exclusions inadequately justified;
  

Analysis

• Parametric tests carried out on obviously skewed data;
  
• Use of multiple paired tests;
  
• Inappropriate analysis of repeated measures or longitudinal data;
  
• Incorrect analysis of matched case-control studies;
  
• Modelling incorrect—e.g. inadequate adjustment for confounders, interaction terms not included, only significant variables
  from preliminary analyses included;
  

Presentation

• Inadequate description of the methodology and statistical procedures;
  
• Inappropriate summary statistics for non-normal data;
  
• No presentation of risk estimates—e.g. odds ratios—and confidence intervals;
  
• Interpretation
  
• Potential bias due to sample selection, no or poor response, missing values, exclusions;
  
• Lack of statistical power not considered;
  
• No allowance made for multiple testing; and
  
• Misunderstanding and misinterpretation of results from models.
  

The Table given below summarises some of the potential problems and their implications which might emerge in the context evaluation of an investigation. A point which must be kept in mind is that even where an investigation is flawed, some useful knowledge might be drawn from it.
The aim of critical analysis is not to discredit or tear down published work, but to ensure that the reader understands its implications and limitations.

Table : Checklist for evaluating published research

Problems which might be identified in a research article	Possible implications
1. Inadequate literature review	Misrepresentation of the conceptual basis for the research
2. Vague aims or hypothesis	Research might lack direction; interpretation of evidence might be ambiguous
3. Inappropriate research strategy	Findings might not be relevant to the problem being investigated
4. Inappropriate sampling method	Measurements might not be related to concepts being investigated
5. Inadequate sampling method	Sample might be biased, investigation could lack external validity
6. Inadequate sample size	Sample might be biased; statistical analysis might lack power
7. Inadequate description of sample	Application of findings to specific groups or individuals might be difficult
8. Instruments lack validity or reliability	Findings might represent measurement errors
9. Inadequate design	Investigation might lack internal validity; i.e. outcomes might be due to uncontrolled extraneous variables
10. Lack of adequate control groups	Investigation might lack internal validity; size of the effect difficult to estimate
11. Biased subject assignment	Investigation might lack internal validity
12. Variations or lack of control	Investigation might lack internal validity of treatment parameters
13. Observer bias not controlled (Rosenthal effects)	Investigation might lack internal and external validity
14. Subject expectations not controlled	Investigations might lack internal and external validity (Hawthorne effects)
15. Research carried out in inappropriate setting	Investigation might lack ecological validity
16. Confounding of times at which observations	Possible series effects; investigation might lack and interventions are carried out internal validity
17. Inadequate presentation of descriptive statistics	The nature of the empirical findings might not be comprehensible
18. Inappropriate statistics used to describe	Distortion of data; false inferences might be drawn and/or analyse data
19. Erroneous calculation of statistics	False inferences might be drawn
20. Drawing incorrect inferences from the data	False conclusions might be made concerning the outcome of an investigation
21. Protocol deviations	Investigation might lack external or internal validity
22. Over-generalisation of finding	External validity might be threatened
23. Confusing statistical and clinical significance	Treatments lacking clinical usefulness might be encouraged
24. Findings not logically related to	Theoretical significance of the investigation remains previous research findings doubtful

(adapted from Polgar and Thomas, 1991)

Sir!
Kindly Give the Names of Some Good Books for the Research,so that we should start it from now.
Thanks
Yours Obediently,
Dr Abu Zar