Benefit-cost ratio calculator blueprint review

[Anton Gritsay]

Questions to be answered:

Is BCR going to become third calculation component? (i.e. is BCR the first calculator for Socio-Economic Impact part of the engine?) Do we intend to introduce [SEI] section to a job config file?

What are the new parameters in job config file?

What is the result format: db, xml, geotiff, etc? Are the changes to NRML schema (input/output) needed?

How do we chain calculators? Do we want to run "Hazard -> Risk -> SEI" or "Risk -> SEI" or just "SEI" alone?

How do we get a loss curve for a retrofitted asset? Should it be another vulnerability model, a function, a coefficient or fixed value in existing vulnerability model?

We also need a complete set of input and matching output (expected) data in order to create a demo and QA-test.

Where is the function that computes expected annual loss? Blueprint says it's implemented.

There is an error in the formula in blueprint: unclosed parentheses.

[Lars Butler (lars-butler)]

Regarding result formats:

I assume that we will want results to be save to the database so that we can visualize data in a GUI. For the first iteration, however, I imagine that we'll have to put more focus on producing file output (likely in some new NRML format); this was the case with the Disaggregation and UHS hazard calculators.

So here's my best guess.
Now: XML
Later: DB

[Vitor Silva (vitor-silva)]

Anton thanks,

The BCR calculator is more like a decision-making tool, that I suggest to be included in the RISK part. This is how we've been presenting this feature for a while and claiming it to be part of the SEI could cause confusion.

For the config_file, we need at least a flag stating the type of calculations (just like we have now for any of the calculators), but the overall structure will be very similar to the Classical PSHA-based risk calculator. We also need another two KEYs. One for the interest rate, and probably one for the life expectancy of the building portfolio.

The result shall be a NRML file, with the list of considered assets, and the associated BC ratio. I guess this information will also be stored in the db.

It is fundamental to create a demo (just like already exists for some of the other calculators), which will be fairly simple. For the QA test, we can create one for the component you'll be developing, but I'm not so sure if it'll be possible to do it end-to-end. Let me think about it a bit more.

I rather discuss the workflow of the calculator in the up coming meeting as it isn't that simple. I hope that with the outcome of the meeting you'll be able to update this entry.

The function that computed the EAL probably close to compute_mean_loss. The function has been implemented about a year ago. It integrates a loss curve. I can help you find this.

Formula corrected.