5 ms·

I found a home to purchase by implementing this. I visited two places to establish criteria, then built a simple search across Greater London on Rightmove usin

by buro9 4y ago

I found a home to purchase by implementing this. I visited two places to establish criteria, then built a simple search across Greater London on Rightmove using area searches with proximity to Waitrose. The results I then filtered again based on price per square foot and rejecting certain keywords (aiming for a price per sq ft between £500-600 without needing renovation, but looking for no chain + quick sale). As soon as a high quality and low price to square foot came up I put in an offer without having viewed it (I did view it once before completion). I live there now... It's a gorgeous apartment purchased about 15% below market rate in a nice area. Implementing a basic solution to the secretary / optimal stopping problem meant that with criteria that took out the vast majority of average places, I stopped on the first one and committed to it.

taurath 4y ago
I did similarly over a few months trying to choose a new apartment to rent. I learned the area and all the types of places that might be available and when one came up that was ideal I jumped on it even though it was in a very low season for apartment availability.
DocTomoe 4y ago
> with proximity to Waitrose I guess this was a "sufficient affluence" indicator to filter out undesireable neighbourhoods? (for readers who don't know: Waitrose is a British high-price-segment supermarket)
- implements 4y ago
  ”Put the papaya down, Orlando!”
- Paul_S 4y ago
  Does that actually work? Just because well-off people shop in Waitrose, does that also mean that houses around Waitrose don't include old council estates?
  - n4r9 4y ago
    It would be somewhat reliable, although - depending on proximity - perhaps not that different from simply drawing a sector around south-west London: https://www.google.com/maps/search/waitrose/@51.505609,-0.3342179,10.18z https://www.google.com/maps/search/waitrose/@51.505609,-0.33... . The rub is that this area is not well-connected to the tube, at least for another 10-15 years.
    - smilespray 4y ago
      There's a single Waitrose south of the river. Huh. EDIT: Okay, 2. Missed the one in Greenwich. Still huh.
  - MafellUser 4y ago
    Most old council estates are privately owned now. Many newer ones are also being sold as shared ownership.
  - retetr 4y ago
    I can't speak for Waitrose specifically, but luxury brands will definitely do a comprehensive analysis of the surrounding area before opening a store. In the US at least, the equivalent is looking for the closest Starbucks or Apple store.
asperous 4y ago
That doesn't implement the algorithm nor does it meet the problem because you were able to evaluate all options and not one at a time (whereas you would need to make a irreversible decision on the spot).
- buro9 4y ago
  Hot housing market with constant stream of options and where the good ones are barely on the market and require an instant decision and full commitment to a quick decision. Unsure what part doesn't meet the criteria, I consciously used that approach to make the decision.
  - StevenWaterman 4y ago
    One of the criteria is a finite, pre-known number of options. In this scenario, you're never forced to buy a house simply because it's the last one and if you don't buy it there's never going to be more houses available.
    - buro9 4y ago
      Finite yes... As otherwise you wouldn't have a stopping problem as you could preselect from all options. What I didn't know is how good each option was, whether to wait for better or not. n is finite as time provides the limit to n. We were looking to move within 6 months (this was a hard requirement based on personal circumstances) and I'd already established the number of likely options according to the rate they appeared on the market.
      - sokoloff 4y ago
        If fewer than 8 places would meet your criteria from among the current inventory plus what comes onto the market in the next 6 months, then you may have used the algorithm. In all of the part of greater London you considered, 7 or fewer possibilities seems quite low, but I don’t know how tight your criteria were in practice relative to that market. If your criteria were that tight, I congratulate you on securing 1 of the 7 suitable properties.
NLips 4y ago
How did you find/calculate the floor area from Rightmove? In my experience listings _might_ have the area in the floor plan image, so you’d be hoping for floor plans then running OCR to find the area? But I’d expect that to often go wrong or not find anything (missing or duplicate floor plans etc). Would love to know as it’s infuriating that the UK market is based on bedroom count rather than floor area.
- maccard 4y ago
  I live in Scotland. The seller has to provide a "home report" which contains this information. It's fantastic!
  - heurisko 4y ago
    We nearly had them in England. :( https://www.theguardian.com/money/2010/may/20/home-information-packs-scrapped-hips https://www.theguardian.com/money/2010/may/20/home-informati...
- OJFord 4y ago
  Bedroom count is ridiculous, it's an estate agent's marketing game whether a room's a study or another bedroom. Should just be #kitchens, #bathrooms, #loos, #other IMO. Number of fitted/room-like cupboards etc. would be a bit useful too, but size so variable it would only give a very rough idea.
retube 4y ago
does rightmove allow filtering by price/sq foot?
appleflaxen 4y ago
This is the same problem, but your algorithm was not n/e. If there are 100 homes on the market, doesn't the optimal algorithm suggest 100/2.718 => 37 homes must be assessed after which you commit hard to the first home that would be above all of those top 37? I mean: you can't argue with the results. You underpaid and are delighted with your home! But you share the problem space without having implemented anything close to the ideal solution. In this case your intuition and sophistication resoundingly /trounced/ the ideal solution in terms of efficiency. So you won!
- shepherdjerred 4y ago
  > If there are 100 homes on the market, doesn't the optimal algorithm suggest It's not about the number of homes on the market, it's about how many homes you want to look at total (which is capped by the number of homes on the market). So, you say that you want to look at 10 homes max. You take 37% of either quantity as the evaluation period. After the evaluation period (3.7 houses) you commit to the first house that's better than the best you saw in the evaluation set.
  - teawrecks 4y ago
    People in this thread also seem to not be aware that the evaluation period can be measured in time as well (as long as the candidates come in uniformly at random, which depending on the time of year, doesn't often happen with houses).
slingnow 4y ago
You didn't implement anything like this, but congrats on finding a home you're happy with using a different algorithm. You only saw 2 homes -- an arbitrary number not at all tied to how many homes might be on the market. You then instantly chose the first candidate you saw above some arbitrary threshold. I hope you can see this is nothing like the optimal stopping problem outlined in the article.

by buro9 4y ago

taurath 4y ago

I did similarly over a few months trying to choose a new apartment to rent. I learned the area and all the types of places that might be available and when one came up that was ideal I jumped on it even though it was in a very low season for apartment availability.

DocTomoe 4y ago

> with proximity to Waitrose I guess this was a "sufficient affluence" indicator to filter out undesireable neighbourhoods? (for readers who don't know: Waitrose is a British high-price-segment supermarket)

implements 4y ago
”Put the papaya down, Orlando!”
Paul_S 4y ago
Does that actually work? Just because well-off people shop in Waitrose, does that also mean that houses around Waitrose don't include old council estates?
- n4r9 4y ago
  It would be somewhat reliable, although - depending on proximity - perhaps not that different from simply drawing a sector around south-west London: https://www.google.com/maps/search/waitrose/@51.505609,-0.3342179,10.18z https://www.google.com/maps/search/waitrose/@51.505609,-0.33... . The rub is that this area is not well-connected to the tube, at least for another 10-15 years.
  - smilespray 4y ago
    There's a single Waitrose south of the river. Huh. EDIT: Okay, 2. Missed the one in Greenwich. Still huh.
- MafellUser 4y ago
  Most old council estates are privately owned now. Many newer ones are also being sold as shared ownership.
- retetr 4y ago
  I can't speak for Waitrose specifically, but luxury brands will definitely do a comprehensive analysis of the surrounding area before opening a store. In the US at least, the equivalent is looking for the closest Starbucks or Apple store.

asperous 4y ago

That doesn't implement the algorithm nor does it meet the problem because you were able to evaluate all options and not one at a time (whereas you would need to make a irreversible decision on the spot).

buro9 4y ago
Hot housing market with constant stream of options and where the good ones are barely on the market and require an instant decision and full commitment to a quick decision. Unsure what part doesn't meet the criteria, I consciously used that approach to make the decision.
- StevenWaterman 4y ago
  One of the criteria is a finite, pre-known number of options. In this scenario, you're never forced to buy a house simply because it's the last one and if you don't buy it there's never going to be more houses available.
  - buro9 4y ago
    Finite yes... As otherwise you wouldn't have a stopping problem as you could preselect from all options. What I didn't know is how good each option was, whether to wait for better or not. n is finite as time provides the limit to n. We were looking to move within 6 months (this was a hard requirement based on personal circumstances) and I'd already established the number of likely options according to the rate they appeared on the market.
    - sokoloff 4y ago
      If fewer than 8 places would meet your criteria from among the current inventory plus what comes onto the market in the next 6 months, then you may have used the algorithm. In all of the part of greater London you considered, 7 or fewer possibilities seems quite low, but I don’t know how tight your criteria were in practice relative to that market. If your criteria were that tight, I congratulate you on securing 1 of the 7 suitable properties.

NLips 4y ago

How did you find/calculate the floor area from Rightmove? In my experience listings _might_ have the area in the floor plan image, so you’d be hoping for floor plans then running OCR to find the area? But I’d expect that to often go wrong or not find anything (missing or duplicate floor plans etc). Would love to know as it’s infuriating that the UK market is based on bedroom count rather than floor area.

maccard 4y ago
I live in Scotland. The seller has to provide a "home report" which contains this information. It's fantastic!
- heurisko 4y ago
  We nearly had them in England. :( https://www.theguardian.com/money/2010/may/20/home-information-packs-scrapped-hips https://www.theguardian.com/money/2010/may/20/home-informati...
OJFord 4y ago
Bedroom count is ridiculous, it's an estate agent's marketing game whether a room's a study or another bedroom. Should just be #kitchens, #bathrooms, #loos, #other IMO. Number of fitted/room-like cupboards etc. would be a bit useful too, but size so variable it would only give a very rough idea.

retube 4y ago

does rightmove allow filtering by price/sq foot?

appleflaxen 4y ago

This is the same problem, but your algorithm was not n/e. If there are 100 homes on the market, doesn't the optimal algorithm suggest 100/2.718 => 37 homes must be assessed after which you commit hard to the first home that would be above all of those top 37? I mean: you can't argue with the results. You underpaid and are delighted with your home! But you share the problem space without having implemented anything close to the ideal solution. In this case your intuition and sophistication resoundingly /trounced/ the ideal solution in terms of efficiency. So you won!

shepherdjerred 4y ago
> If there are 100 homes on the market, doesn't the optimal algorithm suggest It's not about the number of homes on the market, it's about how many homes you want to look at total (which is capped by the number of homes on the market). So, you say that you want to look at 10 homes max. You take 37% of either quantity as the evaluation period. After the evaluation period (3.7 houses) you commit to the first house that's better than the best you saw in the evaluation set.
- teawrecks 4y ago
  People in this thread also seem to not be aware that the evaluation period can be measured in time as well (as long as the candidates come in uniformly at random, which depending on the time of year, doesn't often happen with houses).

slingnow 4y ago

You didn't implement anything like this, but congrats on finding a home you're happy with using a different algorithm. You only saw 2 homes -- an arbitrary number not at all tied to how many homes might be on the market. You then instantly chose the first candidate you saw above some arbitrary threshold. I hope you can see this is nothing like the optimal stopping problem outlined in the article.