I wasn't expecting this to go on hnews yet, but happy to take any questions!
I love the simplicity. Overall, a fantastic product.
Introducing Guesstimate, a Spreadsheet for Things That Aren’t Certain
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Re: Introducing Guesstimate, a Spreadsheet for Things That Aren’t Certain
#72Nice, but I can't help thinking of spreadsheets as something of a crutch. Also check out: http://probcomp.csail.mit.edu/bayesdb/ https://github.com/taschini/pyinterval http://mavrinac.com/index.cgi?page=fuzzpy
In this case it looks like the spreadsheet is mostly for laying out the variables in a nice orderly table/grid.
I'd say in all cases that is what the spreadsheet is for. Otherwise use R.
Re: Introducing Guesstimate, a Spreadsheet for Things That Aren’t Certain
#73I would be much more interested if this product were "choose probability density function centric." Then, the Monte Carlo engine would gain much more interest. Being able to choose or specify arbitrary distributions, and then run simulations, would be valuable.
Of special interest are non-continuous distributions. How often have normal distribution reasoning failed in finance? Put another way, a user should be able to model a distribution himself.
Re: Introducing Guesstimate, a Spreadsheet for Things That Aren’t Certain
#74What fun - I did a monte carlo estimate a few years back when trying to determine what purchases price of house my girlfriend and I could afford. It depended on probable interest rate, how much my old house would sell for, etc. It'd be interesting to see how simply it could be modeled in this.
That seems like a great fit. A few weeks back I used the tool to help a friend decide which mortgage option to take for his house. One house has a slightly lower APR than the other, but was a had a higher assistance fee. After fiddling with it, it looked like the one with the lower assistance fee was the better option. But perhaps more important, it didn't seem like it made a big difference; perhaps around $200 after…
When refinancing houses, I always performed detailed analyses. With a good model, you can compare every deal offered. The key input is your expected life of the loan. You'd pay very high fees for an interest rate reduction if you really thought you'd keep a loan 30 years. But that is not very realistic.
I found, remarkably to me at the time, that at a single particular loan life, the APRs of a single lender all converged very accurately to a single interest rate. This told me two things: 1. Choosing a realistic loan life was key. 2. Many of the choices (points + fees vs. interest rate), were for most people illusory offerings to give the illusion of choice.
Re: Introducing Guesstimate, a Spreadsheet for Things That Aren’t Certain
#75I wasn't expecting this to go on hnews yet, but happy to take any questions!
Have you seen or were you at all inspired by Analytica from Lumina Decision Systems ( http://www.lumina.com/why-analytica )? It's been around for about twenty years and is often used in the field of policy analysis when you need you to quantify messy things like human lives in dollars in the face of massive uncertainties.
Also, Oracle Crystal Ball.
Re: Introducing Guesstimate, a Spreadsheet for Things That Aren’t Certain
#76Isn't how all software should be written? Expressions that represent a set of all possible values, effectively replacing the need for types.
Surely, such a platform would make building an app 100 times easier. Not that building apps is a good use of our resources.
Re: Introducing Guesstimate, a Spreadsheet for Things That Aren’t Certain
#77It seems that using montecarlo in excel is apparently pretty commonm, but I'm not sure if it can be done without addons.
I think DeMarco and Lister did some monte carlo in spreadsheet without addons: http://www.systemsguild.com/riskology
Re: Introducing Guesstimate, a Spreadsheet for Things That Aren’t Certain
#78I would be much more interested if this product were "choose probability density function centric." Then, the Monte Carlo engine would gain much more interest. Being able to choose or specify arbitrary distributions, and then run simulations, would be valuable. Of special interest are non-continuous distributions. How often have normal distribution reasoning failed in finance? Put another way, a user should be able t…
Very good to know. Right now you can choose between normal, uniform, and a few very simple discreet distributions, but not others.
When I built this, my first goal was to make any distribution run quickly. At this point I believe adding other distribution types will be quite doable, expect them shortly.
Re: Introducing Guesstimate, a Spreadsheet for Things That Aren’t Certain
#79hey
nice tool
on a side note what tool did u use to create the animated tutorials on your git page:https://github.com/getguesstimate/guesstimate-app
image link https://camo.githubusercontent.com/8fd97a97fa656a1eb92294f0f...
Re: Introducing Guesstimate, a Spreadsheet for Things That Aren’t Certain
#80I wasn't expecting this to go on hnews yet, but happy to take any questions!
It's nice to see a web app with keyboard support, just please don't highjack the keys if any modifier keys are held down, these are usually for the browser, alt+left to go back as example.