For categorical presentations, indicator groups were established according to quintiles (for indicator bacteria), presence/absence (F+coliphage by CLAT) or at the median (F+ coliphage by SPOT).
The similarities between clinical decision-making and a categorical data analysis and presentation approach can make reading and understanding scientific papers with categorical data easier for clinicians.
We chose categorical cut-points for presentation of the fumonisins and continuous corn exposure variables by calculating the effect of finely categorized variables and then coalescing adjacent categories based on the observed effect estimates (Greenland and Rothman 1998).
Age, included as a continuous variable, was tested for departure from linearity; the results are for ease of presentation, shown as categorical.
Comparison of categorical variables between sites of presentation (ED, general practice, pharmacy) was undertaken using χ tests or Fisher's exact test where required.
Pre-EPAS EPAP imPre-EPAS EPAPand post-EPAS–EPAP implementation differences were identified using inferentiandstatistics; spost-EPAS EPAPann–Whitney U test for non-post-EPAS EPAPtimplementation differencesime to see a clinician, ED LOS) and χ test for categorical data (eg, unplanned re-presentation to the ED, hospital admission, number/type of pathology and other tests ordered).
For the presentation and analysis of categorical variables, frequency distribution, percentages and contingency tables were used.
For ease of presentation, some of the categorical variables were grouped according to clinical significance of the answers, or as the top two versus bottom three answers on a five-point Likert's scale.
Visual presentation of survey questions with categorical response options may allow greater time for processing initial options leading to primacy effects in those inclined to satisfice.
The demographics questions were all class variables, except for age and herd size which were on a continuous scale, but these were re-categorised into categorical variables defined according to quartiles for presentation of the descriptive statistics.
u-LFABP is reported as a categorical variable in Fig. 2 for the presentation of a Kaplan-Meier plot.
