An additional column can be added to
flag information of a particular kind – such as respiratory illnesses. The interval between consultations for respiratory
problems can be calculated and a graph of these intervals over time can show the relationship of symptoms to events such as
Fig 3 is a graph of consultations for asthma per 100 days from a case where the claimant had two successive
jobs and it was uncertain whether her occupational asthma had been caused by the first or second job. This kind of quantitative
approach is very helpful in determining causation.