. . . vs. a Pound of Cure
The “ounce of prevention” — at least for the listing agent (representing the home seller) — is straightforward: when the appraiser (representing the Buyer’s lender) schedules an appointment to view their client’s home, they email or call to introduce themselves.
My usual m.o. is to tell the appraiser a little about the house, briefly chat about how well they know the immediate area, then ask if they’re receptive to seeing my Comps (“comparable sold 
properties”).
Invariably, the answer is “sure.”
Step #2 is to both email the Comps to the appraiser, as well as leave hard copies at the home, along with my analysis.
Even better: meeting the appraiser at the home.
Qualitative vs. Quantitative Info
What’s most valuable to the appraiser is not just the adjustments — the key differences between each Comp and what’s called the “subject home” — but the accompanying explanation(s).
Stuff like, “the reason Comp #1 sold for $30,000 more than this home is because the Kitchen had just been remodeled with custom, cherry cabinets and high-end appliances.”
Or, “Comp #2 sold for $25,000 less because there was a mold issue and the floor plan was terrible.”
Of course, it helps if the listing agent actually knows those things.
Unlike active, experienced agents, who are (or should be) experts about the nearby housing stock, all appraisers have to go on is what they can see on MLS.
For the most part, that info is quantitative (square feet, home style, construction date) vs. qualitative (“Comp #3 had been a rental for the last 3 years, was dirty, and showed poorly”).
Appeal Odds
So, what’s the pound of cure?
Not doing the foregoing, and dealing with the fallout from a home that doesn’t appraise.
While appraisers can make mistakes, and it’s possible to appeal a low number . . . the odds ain’t great.
Depending on the lender and the case-specific facts, the odds of success are only 5% – 10% — and that’s after formally marshaling all the information discussed above, navigating the lender’s forms and paperwork, etc.
While that process is playing out, the listing agent needs to spend a not inconsiderable amount of time and energy keeping their (understandably upset) client informed, reassured, etc.
Starting From (Worse Than) Scratch
Assuming the low appraisal number stands, there are really only two outcomes: 1) the Buyer and Seller renegotiate a new (lower) sales price; or 2) they don’t.
Obviously, #1 is preferable.
However, if the Buyer can’t — or won’t — put more cash into the deal, or the Seller can’t take less (because they’d be underwater), or the Seller is adamant that the appraisal is mistaken and won’t take less . . . no deal.
In that event, the home typically comes back on the market . . . and the listing agent gets to start from scratch (never mind the Seller).
In fact, worse than scratch.
That’s because switching a home from “Pending” back to “Active” is a yellow flag for all prospective new Buyers.
It’s also the case that, depending on the time of year, a swing of 3-4 weeks can make a big difference in a home’s saleability.
In Spring, no big deal.
However, whether a home debuts on the market in mid-November (now) vs. a month from now, when the holidays are in full swing, can matter a LOT.
See also, “More Than This, Less Than That“; “Why the Neighbor’s Home Isn’t a Comp“; “Real Estate Bracketing ” Advanced Beginner Version;” “The Science ” and Art ” Doing Comp’s“; and ““Bracketing,’ Explained.”
