Even USPAP says perfection is not possible.
I have said it before, no valuation method, whether a traditional appraisal, a hybrid or an alternative method such as an AVM is "foolproof." That is because market value is a concept, not a fact. Yet we deal with facts to arrive at market value. However, it is not each fact in isolation which matters, or even a factual error ( unless substantial enough to impact value opinion ) Does a borrower really care if a house is 2100 sf vs 2070 sf? Probably not. Focusing on an error of 30 sf off in measurement or other source is inane then. However, a borrower might care if the house was 1800 sf. And that would be enough to impact value.
The problem is compounded in that no measurable adjustment exists between lot size variances ( 900 sf vs 9800 sf ) or year built when similar ranges ( 1960 or 1967 ) . Yet a software program might be mechanically adjusting for such differences.
Buyers purchase properties typically for the combination of features, it ticks off the boxes for what they want ( a 2000 sf range house on a decent-sized lot in a certain area.) And then, there is often a driving factor about a property as well - such as a lake view. The buyer always wanted a lake view, is willing to pay for it, or has a boat. So the lake view might get a disproportionately larger adjustment than other factors might.
Imo, computer stats are the best at market condition adjustments but might be off in other areas - or they could support adjustments made that the comps itself on the grid show. Which method to rely on the most ( the comps on grid for extraction, statistical models, cost derived, RE agent survey) etc can vary by assignment. And more than one source of support for an adjustment is best.
If quality is the goal, the mad race for turn time needs to slow down. It is antithetical to have the time needed for analysis with the often unnecessary speed race. One day more when the validation is well ahead of what is needed to close won't matter. Breakneck speed all along the line is foolish if the stakeholders are concerned with risk. ( speed in underwriting, income verification, valuation, all of it ) - is being ratcheted up for no particular reason. RE sales are not online sneaker purchases. If a borrower can not understand that, they probably can not function well enough to make payments on a home. Same thing for refinances. If someone is so desperate that they need the money tomorrow, maybe they are not a good credit risk. That said, of course, delivering in a timely manner is the goal.
Lastly, if the GSEs;s and stakeholders are as concerned with risk as they claim, they need to address the AMC fee payment structure. The GSEs;s could simply state that any loan they back if an AMC is used must have the C and R fee from the borrower as the fee paid to the appraiser and the lender pays the AMC fee as a cost. The GSEs;s can do that, they can do whatever they want in setting loan conditions. They had no problem setting a payment condition when they let the lenders know a buyer paid RE broker fee is not considered a concession by them and thus can be placed in the seller column. The lenders can pass on the AMC fee to the borrower or absorb it as a cost. Or they can dump the AMC and form their own panel. I am well aware this action from the GSE's is highly unlikely to happen, but they and others should consider a solution to this problem if they truly believe appraisers have a valuable place in the valuation system - then they need quality people, not just people willing to take the lowest fee and then pump out whatever they can to survive. That is not the way to maintain a viable profession.
In sum, the facts matter, but by themselves or even when organized into a format and adjusted for in an AVM or by an AI system, the facts alone are not enough. An integrated view of the whole of the property, mirrors how buyers consider it, as well as the key driving factors of value ( a view, or close distance to an urban center, etc) need to be reconclied and analyzed and since people are the buyers nd sellers, people are the ones who can decipher their motivaitons and reconlice them with the condions and terms of market value.