3 ms·

We’re not currently including mortgage insurance, no. You could approximate it by increasing the mortgage rate, but the tax treatment of mortgage insurance paym

We’re not currently including mortgage insurance, no. You could approximate it by increasing the mortgage rate, but the tax treatment of mortgage insurance payments may be different and so that may not be accurate. Perhaps this is something we can add in the next iteration of the calculator. The interaction between down payment rate and mortgage insurance rate also reveals a limitation of our user interface: On the one hand, it’s nice to have all the variables decoupled so that you can set and explore them independently. On the other hand, many of the variables are not independent. If you change one variable, you may need to change other variables to maintain a realistic scenario. Having the mortgage insurance rate tightly coupled to the down payment would probably be too limiting, but maybe there’s a still a way to better identify when certain variables (or combination of variables) are unrealistic.

pessimizer 12y ago
Maybe instead of just having reasonable defaults, you could include reasonable ranges through a background gradient on each graph (darker for more common, lighter for less common)? With that, you could manipulate the reasonable ranges through interactions between graphs, while still allowing people to set the actual number anywhere they pleased. Also: big fan. Thanks for d3.
- mbostock 12y ago
  Definitely. We actually designed something like that, but due to time constraints weren’t able to ship it (yet). One complication is that a reasonable range for a given variable can depend on other variables. But hopefully we’ll figure it out. And thank you!
  - nitrogen 12y ago
    I'm sure you've seen TangleJS by Bret Victor. Its performance wasn't quite good enough for the way I wanted to use it, but it looks like that level of meta-interactivity is what you're going for. Here's my favorite demo of the concept, discovered here on HN: http://worrydream.com/#!2/LadderOfAbstraction http://worrydream.com/#!2/LadderOfAbstraction
    - GFischer 12y ago
      Wow, that's an impressive site, thanks for sharing. I think I had seen the one on the future of interaction design, but I hadn't explored the site :) .
roel_v 12y ago
"The interaction between down payment rate and mortgage insurance rate also reveals a limitation of our user interface: On the one hand, it’s nice to have all the variables decoupled so that you can set and explore them independently. On the other hand, many of the variables are not independent. If you change one variable, you may need to change other variables to maintain a realistic scenario." Well I'm not sure I'd call this a 'limitation' of your UI. This is actually a very common issue when designing user interfaces for models (I have been doing this for a living for almost 15 years). There is a continual tradeoff between the positives of the software ensuring internally consistent, and realistic, values - and allowing the user flexibility for edge case exploration. And then there are issues like discoverability, speed of use, technical limitations, etc. - as always. One of my favorite mental toys in this area is: devise a way for a user to assign a fixed amount (call it a 'budget') to several categories. For a simple example, consider a budget of $100 over 5 expense categories. But it should also work for allocating a road maintenance budget across 25 districts, or for assigning a weighting to the importance of policy objectives (ecology, health, economic growth for example). In the vast majority of cases, after several meetings about this, clients say 'fuck it, let them copy/paste their own values from Excel' (at this point I come in and broker a truce between the warring factions of several solutions and implement a meet-everybody-halfway solution :) ) It's one of those 'how hard can it be?' <2 weeks later> 'oops yeah pretty hard' things.
- cbr 12y ago
  devise a way for a user to assign a fixed amount to several categories A slider for each category. When one slider is moved up by 1% of the total the others automatically move down in proportion to their current value to collectively lose 1% of the total.
  - roel_v 12y ago
    Yes, this is the first instinct. But moving all of the others down/up is in the majority of cases not what you want. Imagine you have 100 to spread out over 4 categories. Let's say you start with setting them all to 25. You set the first to 33, then you want to set the second to a desired values except oops, the first one is now no longer 33. Basically in this scenario you have to way to set them all to a precise value without trial and error until you're close enough to what you want.

pessimizer 12y ago

Maybe instead of just having reasonable defaults, you could include reasonable ranges through a background gradient on each graph (darker for more common, lighter for less common)? With that, you could manipulate the reasonable ranges through interactions between graphs, while still allowing people to set the actual number anywhere they pleased. Also: big fan. Thanks for d3.

mbostock 12y ago
Definitely. We actually designed something like that, but due to time constraints weren’t able to ship it (yet). One complication is that a reasonable range for a given variable can depend on other variables. But hopefully we’ll figure it out. And thank you!
- nitrogen 12y ago
  I'm sure you've seen TangleJS by Bret Victor. Its performance wasn't quite good enough for the way I wanted to use it, but it looks like that level of meta-interactivity is what you're going for. Here's my favorite demo of the concept, discovered here on HN: http://worrydream.com/#!2/LadderOfAbstraction http://worrydream.com/#!2/LadderOfAbstraction
  - GFischer 12y ago
    Wow, that's an impressive site, thanks for sharing. I think I had seen the one on the future of interaction design, but I hadn't explored the site :) .

roel_v 12y ago

"The interaction between down payment rate and mortgage insurance rate also reveals a limitation of our user interface: On the one hand, it’s nice to have all the variables decoupled so that you can set and explore them independently. On the other hand, many of the variables are not independent. If you change one variable, you may need to change other variables to maintain a realistic scenario." Well I'm not sure I'd call this a 'limitation' of your UI. This is actually a very common issue when designing user interfaces for models (I have been doing this for a living for almost 15 years). There is a continual tradeoff between the positives of the software ensuring internally consistent, and realistic, values - and allowing the user flexibility for edge case exploration. And then there are issues like discoverability, speed of use, technical limitations, etc. - as always. One of my favorite mental toys in this area is: devise a way for a user to assign a fixed amount (call it a 'budget') to several categories. For a simple example, consider a budget of $100 over 5 expense categories. But it should also work for allocating a road maintenance budget across 25 districts, or for assigning a weighting to the importance of policy objectives (ecology, health, economic growth for example). In the vast majority of cases, after several meetings about this, clients say 'fuck it, let them copy/paste their own values from Excel' (at this point I come in and broker a truce between the warring factions of several solutions and implement a meet-everybody-halfway solution :) ) It's one of those 'how hard can it be?' <2 weeks later> 'oops yeah pretty hard' things.

cbr 12y ago
devise a way for a user to assign a fixed amount to several categories A slider for each category. When one slider is moved up by 1% of the total the others automatically move down in proportion to their current value to collectively lose 1% of the total.
- roel_v 12y ago
  Yes, this is the first instinct. But moving all of the others down/up is in the majority of cases not what you want. Imagine you have 100 to spread out over 4 categories. Let's say you start with setting them all to 25. You set the first to 33, then you want to set the second to a desired values except oops, the first one is now no longer 33. Basically in this scenario you have to way to set them all to a precise value without trial and error until you're close enough to what you want.