Using FRP to calculate risk-based guardrails

[TomS]

I upgraded to a paid subscription to FRP because of the great features it has that help me do the calculations for risk-based guardrails. Just wondering if anyone else here uses it for that, and if so, what your methodology is?

I’m basing mine on a couple of Kitces articles that describe it. The first one provides a pretty simple approach and is what I initially was going to go with. https://www.kitces.com/blog/guyton-klin ... isk-based/

The next one goes into more detail, recommending that spending adjustments be presented in dollars. https://www.kitces.com/blog/probability ... unication/
The calculations include the following:

1. Spending level at the initial/target probability of success
2. Portfolio value that increases the probability of success to the upper guardrail
3. Spending level at the upper guardrail portfolio value that fulfills the upward adjustment rule
4. Portfolio value that decreases the probability of success to the lower guardrail
5. Spending level at the lower guardrail portfolio value that fulfills the downward adjustment rule.

Quoted from a comment at the bottom by the article author, Derek Tharpe - http://disq.us/p/2fhrvd0

The ability to set a POS target in FRP and have it calculate either the spending level or needed portfolio size makes doing these calculations pretty straightforward, but when I tried doing it using my numbers I found the results confusing. I ended up with a lower spending number after doing the upper guardrail spending adjustment. That couldn’t be right - it should’ve been a higher spending number after portfolio hits upper guardrail.

Anyway, just wondering whether anyone else has come up with an approach for calculating annual SWR using a guardrails methodology and FRP. Thanks.