Data collection, modelling validation

Survey of damage experts

floodam.building relies on the modelling of expert knowledge. Two types of experts who have an experience of how buildings are affected by flooding have been surveyed :

• insurance adjuster: expert in charge of assessing claims after the occurrence of a flood. This expert is mandated by insurance companies to record damage, to estimate what type of actions are needed (reparation or replacement), and to estimate theirs costs.
• building expert: expert in charge of inspecting buildings to check their integrity. This expert may be mandated by insurance companies when buildings display defaults compared to the norm of construction.

These experts have been surveyed on their knowledge on the damage processes and actions needed when damage occurs. We asked them:

• to validate how we model damage processes in general in comparison with their experience (the fact that we consider the total damage as the sum of damage to elementary components, but also the fact that we define the damage as the sum of the costs of the actions to be taken when elementary components are altered, and the fact that we relate the probability of alteration to some flood parameters);
• to specify as precisely as possible the damage mechanisms, and their relationship to the hazard parameters.

We surveyed 14 insurance adjusters and one building expert. We took into account both their specialty (buildings, types of equipment, types of furniture, stocks) and the region where they usually work (details are given in table Table 1. The survey was conducted in five steps:

• first step: it was based on focus groups, where experts were grouped by region. We presented the way we model damage processes, the usage we planned for this model. We asked for any commentary, positive or negative. We also asked the experts information about their specialty and the types of buildings they were the most familiar with (shops, banks, restaurants,…);
• second step: it was based on individual interviews. We asked specific questions on damage processes for elementary components within each expert’s specialty;
• third step: it was based on focus groups, where experts were grouped by specialty. We reported our comprehension and modelling of the second step, showed the implications on damage estimation, and presented the differences between experts, possible inconsistencies or lacks. Experts were asked to made any comments they found useful, and that we should take into account to improve the modelling;
• fourth step: it was based on written exchanges. The aim was to validate the feedbacks from the third step;
• fifth step: it was based on a focus group. We met insurance adjusters that did not participate in the first four steps and presented them the results of the whole study. Again, the experts were asked to made any comments they found useful, and that we should take into account to improve the modelling. However, at this stage, the experts did not ask for further changes;

Table 1

Data on costs

The costs of the actions were defined according to lessons learnt during the survey of experts:

• Some costs of repair were directly given by insurance adjusters. This was the case for very frequent repair costs.
• For the costs of repair of specific devices (which may be present in some activities), insurance adjusters explained to us that, in practice, they would ask the manufacturers to assess these values. Nevertheless, they indicated the relative damage to such devices, depending on their nature (mechanical, electrical, electronic).
• For repair costs concerning building components, the building expert gave us estimates based on batriprix. Batiprix is a price catalogue specialized in building construction.
• For replacement costs concerning the contents of the building, insurance adjusters advised us to use prices catalogues.