GLA Adjustments

[Tom D]

Any chance I could get this spreadsheet from you and try it out?

All these GLA adjusters are only accurate when comps have bracketed GLA's and somewhat a close range.
This program you can adjust it for how many comps you use. I use only 3, seems to have worked the best.
The number you get isn't necessarily the one you use, but it usually leads to a start. You can change the main number, because of sensitivity, it gives you. I put that graph in report. I don't feel like explaining every time i set a GLA number. The graph at minimum shows that i used something besides 'the sheet' to determine the GLA adjustment. Graphs are visual aids of your explanation.

If you can show it 2 ways, then you will be never asked.

 

[Zoe]

All these GLA adjusters are only accurate when comps have bracketed GLA's and somewhat a close range.
This program you can adjust it for how many comps you use. I use only 3, seems to have worked the best.
The number you get isn't necessarily the one you use, but it usually leads to a start. You can change the main number, because of sensitivity, it gives you. I put that graph in report. I don't feel like explaining every time i set a GLA number. The graph at minimum shows that i used something besides 'the sheet' to determine the GLA adjustment. Graphs are visual aids of your explanation.

If you can show it 2 ways, then you will be never asked.

Yeah, sensitivity analysis is a form of regression analysis. A person can start with $X per sq ft of GLA in grid and then make all other adjustments. After that it is regression analysis on what brings the indicated values closest together and how I adjust for GLA. It is basically standard deviation which is regression analysis.

The number I start with on GLA adjustment will change by the time I am done in final reconciliation on sales comparison approach.

 

[Zoe]

I have known some very good residential appraisers that round the GLA adjustment to nearest $5. They use sensitivity analysis.

Then qualitative analysis comes in on which comp(s) is given the most weight.

 

[J Grant]

There is no set formula, but to start with for a sensitivity analysis, ( can use the comps and add sales if needed to the grid), to start with, half of cost to build is a reasonable place to start and then the adjusted range will show you if the amount needs to increase or decrease. A house that costs $150 a sf to build might start off, for example, by applying $75 a sf, and you might end up with $90 a SF.

The OP example of their grid in post 24 has issues that make applying an SF adjustment problematic. The value range is in the opposite direction it is supposed to. The unadjusted raw prices are a tighter price range and applied adjustments result in a wide adjusted value range. It is supposed to work the other way around ( a wider raw price range is tightened by applying adjustments)

Comp 3 looks to be the problem, as a 1.6-acre home selling for far more than a house with 7 plus acres , might indicate Comp 3 is from a superior area - idk. But the acreage is so small compared to the subject 5 acres, it seems like a poor choice even if horses are allowed. It looks like the subject lacks a barn, and not everyone who lives in equestrian allowed zoning owns a horse.

The time/market conditn adjustments make no sense because comp 1 and 2 have positive direction and comp 3 a negative time adjustment. The time adjustments look enormous, is that area rapidly appreciating or declining in such a short time -
They came here looking for a program to spit out a time adjustment and nobody can provide one, the folks who gave software or excel suggestions it looks as complex as applying simple sensitive analysis to the comps on the grid - but an appraisal with serous comp choice or time adjustment of other issues is not going to be saved by even a well devbelped time /market condition adjustme.t It looks like this OP might be over-applying the time adjustment - the rapid appreciation has slowed in many areas per posts here.

 

[OG80]

What market are you in where prices are increasing 36% annually. That seems somewhat unbelievable.

Perhaps but it's rural. 1100-3000 GLA and lots over 1 acre. Not a lot of choices. Went out 15 miles.

 

[J Grant]

I go back further int time to get good comps in these types of situations. But I am typically not applying such huge time adjustments so an 18 month old comp is useble in most cases. I agree with the OP that the 2 bedroom vs 3 bedroom is not much of an issue considering that most of the comp choice is abut lot size.

 

[Zoe]

Perhaps but it's rural. 1100-3000 GLA and lots over 1 acre. Not a lot of choices. Went out 15 miles.

Nothing wrong with going back like 3 years on land sales. Your market condition adjustments concern me most.

 

[Zoe]

You have big market adjustments on 2 comps and a big negative adjustment on one comp for market condition adjustments.

That bothers me.

 

[Zoe]

You ask lender for a redo.

 

[Zoe]

Look at this chart. May be only reason Fed lowers fed funds rate.

Average Sales Price of Houses Sold for the United States

Graph and download economic data for Average Sales Price of Houses Sold for the United States (ASPUS) from Q1 1963 to Q2 2025 about sales, housing, and USA.

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