Some interesting thoughts...
How important is a difference of, say, 66 square feet? 66SF as a percentage of what total square feet or GLA? If your adjustment for GLA is, say $25 a foot...that would be $1650. If it was $50 a SF that would be $3,300. What percent of total value is that?
Well, I didn't want to get into the issue of GLA adjustment factors, buuuuut .........
I use the market - some of my old mentors (residential ones, not the commercial guys) had a Cost/SF ratio rule, which I hate to admit, I used for a while when I was a trainee - but I always thought it was crap.
Realtors market and sell (push might be more appropriate) based upon price/SF and the general buying public, being the conglomerated pack of sheep it often resembles, swallows it. As a result, statistical analysis, no matter what you adjust out first (and assuming you're NOT using outrageous factors like $10K for a fence, or $15K for a culdesac location) will always show that $/SF is the trend line the data will group most tightly around (i.e. the one with the least variance).
Since the actions of willing buyers and sellers CREATES the market, the way they make their decisions en-mass (regardless of what degree one side may be getting fleeced) should be reflected in how we analyze the market.
The model I've created extracts market conditions first, then applies necessary adjustments to the orginal sale prices of a large group of sales (preferably at least 50). I then develop independent graphs for price vs. age and price vs. GLA. The results from each graph get fed back into each in other by a looped macro until changes created as the feedback look runs disappear to almost zero. This results in $/SF and $/YR adjustment factors which produce an adjusted data set with the least variation possible when factoring in Size (GLA) and Age.
Because pools have considerable value here in Florida, and since public records in these parts tell me Y or N, I actually run that model for both pool and non-pool homes. The difference in the two data sets gives me a very nice 2D model for pool ajustments based upon the size of the home and its age
Having said all that, the adjustment factor for $/SF in this neighborhood is around $120/SF (or was back in Jan/Feb).
This guy used $30/SF - so in his report, you are right.... the resulting error is not much in terms of percentage on a $250K+/- home. But only because he's using the wrong adjustment factor, IMO.
I'm not going to try and wage that battle with FREAB - If I did, the only argument I would have is based upon the prevailing method used by our peers - and don't believe there is ANY consensus on that matter, nor do I think most appraisers would be honest if asked by a Board member - I believe 80% of the residential appraisers who got certified since 2001 use the above mentioned "ratio of Cost/SF" and tout the maxim that "you can never adjust more/SF in the SCA than the cost-new or depreciated cost (take your pick), or they use the tried and true(ly worthless) "wet-thumb-in-the-air" method.
I think my way of doing it is pretty damned spot-on, or I wouldn't waste the considerable time it takes to do it, nor would I be trying to develop a PHP/MySQL database system to automate it and build a pwerful analytical capability within my market. IMO, there is much resistance to doing things that way because of the level of ability in a couple of disciplines necessary to do it. In the future, with increased educational requirements now in effect, we should have more appraiser's with better statistical and analytical backgrounds. I think then my method, or something like it, will become the dominant way
I think I'm going to start a new topic on this one - I searched, and the most recent one I could find was from 2005
Lastly, remember, people who live in glass houses should never throw rocks. If you decide to file a complaint be sure your shorts are squeaky clean.
I definitely hear you... and I've considered it. I believe I have been as thorough in my practice of this profession as I can possibly be and I am constantly trying to find chinks in my armor - many of my supplemental addendums approach 4 & 5 pages because of my commercial background and an old MAI who routinely cut me off half-way through asking a question with "DISCLOSE IT!!" Another mentor I had told me "Never underestimate the ability of a bureaucrat to find fault with you if he feels either inconvenienced, defensive, or just needs to look like he's doing something."
Hopefully, even if I forget to change my underwear, I've managed to trade any glass panes for 2" Lexan - yeah, das it... I'm bullet proof, baby!:new_2gunsfiring_v1:
Regardless of how bureauc.... err bullet-proof I am, or am not, the superstructure of my house is irrelevant because the moles, termites, gophers, snakes, and wandering sewage-soaked roots (suiting analogies to what everyone around here calls "skippy") are destroying the foundation my house is built on. If all of us don't start taking action VERY soon (like yesterday) I can throw all the rocks I want because I'll be living iN A VAN, DOWN BY THE RIVER!!!