Showing similarity of results given by two methods: a commentary.
There is a frequent need in the environmental sciences to show the similarity of the results given by two analytical methods. This cannot, however, be done within the conventional 'there is a difference' statistical hypothesis setting of, among others, Student's t-test. We demonstrate here a more appropriate approach that originates from drug testing and that can be applied with standard statistical software. It is a challenging approach, as it requires quantification of the similarity limit. If no pre-determined value is given for similarity, a potential data-supported similarity limit can be explored from the data. The approach has numerous other potential application areas, e.g. parallelism of regression slopes, homogeneity of variances and lack of interaction.
Rita
Hannu
H
Finnish Environment Institute, P.O. Box 140, FIN-00251 Helsinki, Finland. hannu.rita@helsinki.fi
Ekholm
Petri
P
D003627:Data Interpretation, Statistical; D004463:Ecology / Q000379:methods*; D015233:Models, Statistical; D012984:Software; D013810:Therapeutic Equivalency