Raam outputs

[lenkahas]

Hi,

I am looking at using your RAAM model, but I'm a little confused about the code.
I was hoping you would be able to explain in further detail three things.

1. I am not really sure what exactly the output number of the RAAM model represents, is it the fractional deviation from the national mean as shown in Figure 1 in your paper? if yes then that means the final number to be the RAAM(r)/RAAM - 1, in which case what does the RAAM raw number represent?
2. Am I right saying that if I want to incorporate weighting on the distance in the cost matrix, in the Raam model, I need to do that outside the function.
3. I would like to incorporate the distance buffer (tau) and I think what you guys do is as simple as distance/tau, but I just wanted to confirm that and ask if there is any effect of applying weights on the RAAM output and if that needs to be accounted for in the interpretation.

[JamesSaxon]

Thanks @lenkahas, for writing.

I am not really sure what exactly the output number of the RAAM model represents, is it the fractional deviation from the national mean as shown in Figure 1 in your paper? if yes then that means the final number to be the RAAM(r)/RAAM - 1, in which case what does the RAAM raw number represent?

The paper showed the fractional deviation from the national mean. Depending on how you set normalize, the values outputted by the code will either be normalized to 1 over your study area (i.e., divided by the mean -- not nationally of course, unless your study area is national), or it will be the raw value of of RAAM. The code doesn't subtract off the mean (to give the deviation).

Am I right saying that if I want to incorporate weighting on the distance in the cost matrix, in the Raam model, I need to do that outside the function.

Correct, if you want to change the cost function other than by τ, this implementation requires you to change the cost matrix.

I would like to incorporate the distance buffer (tau) and I think what you guys do is as simple as distance/tau, but I just wanted to confirm that and ask if there is any effect of applying weights on the RAAM output and if that needs to be accounted for in the interpretation.

I think you are again correct in your understanding. In the paper, we did describe modifications to the model in the section "Variable Disutility of Travel." But that was in our different c++ code. If you wanted to to control the weighting scheme, you could set τ = 1 and then apply any function to the cost matrix.

Please close the issue if this answers your question.

[lenkahas]

tHis is really helpful, thank you