Appraisal & common methodological issues
A number of important research methodological issues were frequently identified in research investigating potential risk factors for human-directed dog aggression.
The appraisal process involved examining each asset of a study outlined below in order to determine the quality of evidence, for risk factors of human-directed dog aggression, provided by the work.
Several important methodological issues were identified in the studies; these are outlined below. Within the database some of the limitations of each paper have been identified using the same headings as below. Neither list is exhaustive.
- Absence of comparator group.
- Absence of sample size calculations.
- Small sample size, leading to high chance of insufficient power to detect effect.
- Convenience sampling.
- Selection of controls from different population to cases.
- Use of registries as comparator.
- Lack of randomisation.
- High risk of bias.
- Lack of clear definition of outcome - for example what is meant by "bite"?
- Non-reproducible or subjective measurement methods.
- Lack of standardisation.
- Absence of blinding.
Lack of control of confounding through design and/or analysis
- Inappropriate methods.
- Univariable analyses where multivariable would have been appropriate.
- Multiple statistical tests - increasing the likelihood of chance findings.
- Lack of a clear hypothesis.
- Causal relationships identified where direction of association unclear.