Appraisal Statistics: Regression - Do Your Really Know How Much Work It Is?

[Joe Flacco]

Oh boy....wait till Joan hears about this!

What does MARS have to do with Joan?

 

[RCA]

Data for 80% of factors and differences for residential real estate is not even collected anywhere. What and how differences impact a certain property depends on the property. I p iss on your MARS. It sounds to me like you do not understand residential real estate.

This is a data set that was collected in 1970. No it is not the property data we work with today. But it is housing data, it has a target variable and predictor variables just like our data. It is however useful to use it as a benchmark. Salford Systems uses it, competitions like Kaggle use it, there are courses that use it for an example and so on.

My MLS data comes from the MLS of course. But, I am restricted from displaying it on a website; because of license agreements. So, this really is quite useful.

Don't feel bad you can't deal with it. But the point is, a regression tool can grind through tons of complex data; whereas manual methods are rather slow and constrained.

If you don't like my data, you can provide a test set yourself. I can always run it through MARS.

By the way, I attached a CSV file with the original data (no corrections) that I obtained from the Kaggle website. It was used in a recent competition. (Remove the .txt extension after downloading.)

 

[Evincere]

I'm of the opinion residential appraisers should avoid trying to mimick avms altogether and be better at the basics.

I agree and am of the opinion that instead of remaining distinguished we are being persuaded into a process in which a minority group (Appraisers) comes to resemble those of a dominant group (AVM) which to this day considered still very unreliable regardless of how fast or how much complex data they (may be capable) of grinding through. .

 

[RCA]

I agree and am of the opinion that instead of remaining distinguished we are being persuaded into a process in which a minority group (Appraisers) comes to resemble those of a dominant group (AVM) which to this day considered still very unreliable regardless of how much complex data they (may be capable) of grinding through. .

Well you are on an "Appraisal Statistics: Regression" thread, what do you expect? I did ask for a separate sub-forum for statistics. But someone higher up decided it would better I guess to expose the general group to these ideas.

 

[Joe Flacco]

This is a data set that was collected in 1970. No it is not the property data we work with today. But it is housing data, it has a target variable and predictor variables just like our data. It is however useful to use it as a benchmark. Salford Systems uses it, competitions like Kaggle use it, there are courses that use it for an example and so on.

My MLS data comes from the MLS of course. But, I am restricted from displaying it on a website; because of license agreements. So, this really is quite useful.

Don't feel bad you can't deal with it. But the point is, a regression tool can grind through tons of complex data; whereas manual methods are rather slow and constrained.

If you don't like my data, you can provide a test set yourself. I can always run it through MARS.

I consider way many more variables than is recorded anywhere. Your stupid software doesn't grind through any data that is not collected. Width of a lot, width of the house, width of a condo unit, is it a corner unit, does a property back to an alley, floor plan. The list goes on and on.

You can take your MARS and take a hike.

 

[Joe Flacco]

I agree and am of the opinion that instead of remaining distinguished we are being persuaded into a process in which a minority group (Appraisers) comes to resemble those of a dominant group (AVM) which to this day considered still very unreliable regardless of how fast or how much complex data they (may be capable) of grinding through. .

It is unreliable because they only have 10% - 20% of the data to analyze. These morons are scratching their heads like gee, I wonder why we can't solve the puzzle.

 

[Joe Flacco]

Let's collect site size, GLA, view ratings, location ratings, number of garage spaces, bedrooms, bathrooms, q and c ratings and see if we can reliably value the real estate throughout the country. It's a joke.

 

[Evincere]

Well you are on an "Appraisal Statistics: Regression" thread, what do you expect? I did ask for a separate sub-forum for statistics. But someone higher up decided it would better I guess to expose the general group to these ideas.

And the asking was probably a good idea for those who would be interested in long term discussions. Otherwise, The reality is that like all other threads it will recede into the archives.

And btw I would venture to say those reading this thread are not walking around in prehistoric loin cloths. These “ideas” are not new to any of us.

 

[Evincere]

“In any case, I think you can see, it can be a lot of work to add in the variable values that may be missing from your MLS data and then tweak the model by seeing if you can improve your supplied (most likely subjective) values. Also, you should be able to understand why AVMs are so far off - as they don't know the values of all the important contributors to value that are typically not in the MLS or at least cannot be estimated very well from the data in the MLS. [ But interestingly, if the AVM companies can get some of that data, they can use it to incrementally improve their models - thus the interest in getting their hands on appraiser data.]”

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Neither Appraisers nor AVMs will ever be able to predict objectively or subjectively by crunching large data sets or by using 6 comps the reasoning (even with MLS data) when all factors being equal the why of why the wife liked the white granite countertops over the beige or the slate vs bamboo flooring. Or that the property was closer to the school bus stop. Subjectivity is relative and greatly contributes to value. These are equations no AVM will ever master to improve their models. Subjectivity which AVMs are designed to not consider IS the outlier to a fault.

Presuming that subjectivity has relevance to value, given the typical appraisal time constraints Appraisers must work within and the financial and personal time investments do you honestly believe RA to really be a worthwhile investment?

 

[RCA]

“In any case, I think you can see, it can be a lot of work to add in the variable values that may be missing from your MLS data and then tweak the model by seeing if you can improve your supplied (most likely subjective) values. Also, you should be able to understand why AVMs are so far off - as they don't know the values of all the important contributors to value that are typically not in the MLS or at least cannot be estimated very well from the data in the MLS. [ But interestingly, if the AVM companies can get some of that data, they can use it to incrementally improve their models - thus the interest in getting their hands on appraiser data.]”

Neither Appraisers nor AVMs will ever be able to predict objectively or subjectively by crunching large data sets or by using 6 comps the reasoning (even with MLS data) when all factors being equal the why of why the wife liked the white granite countertops over the beige or the slate vs bamboo flooring. Or that the property was closer to the school bus stop. Subjectivity is relative and greatly contributes to value. These are equations no AVM will ever master to improve their models. Subjectivity which AVMs are designed to not consider IS the outlier to a fault.

Presuming that subjectivity has relevance to value, given the typical appraisal time constraints Appraisers must work within and the financial and personal time investments do you honestly believe RA to really be a worthwhile investment?

If you want my estimate, then I would estimate about 15% of residential appraisers - many of whom are apparently too busy to spend time on this forum - because they have too much work to do.