Results of the regression tree analysis by predicting results from the three European Centres and subjects from Montreal and vice-versa
| Final diagnosis | OA | A | No OA, no A | Total |
| OA | 34# | 33 | 5 | 72 |
| A | 35 | 46# | 9 | 90 |
| No OA, no A | 9 | 33 | 8# | 50 |
| Total | 78 | 112 | 22 | 212# |
OA: occupational asthma; A: asthma. #: number of situations in which the model correctly predicted the actual situation (88 out of 212 cases; 42%).