Better known as the "Drive-by", clients sometimes think that these appraisals are less work and easier than a standard traditional appraisal. Actually, the amount of work at the desk is the same, and in some cases more time consuming than a regular interior appraisal. Why?
Sometimes there the county data has sketchy information about the house, such as room count, year built, gross living area, etc. To verify this, I have to make calls, search other data sources, and sometimes told by the client to "estimate" the data. In some cases, where the lack of data would not produce reliable results, I will decline the order. I would gladly avoid all this by just walking into the house to get clear and accurate data.
Apart from this, the research and analysis, which is the bulk of the work, is identical to interior appraisals. The 1004MC form is still required, as well as all the narrative needed to support client requirements. The only time saving quality of these types of assignments is that I don't have to schedule an appointment and inspect the home, which in relation to the whole, is not a big deal.
So in summary, if you are considering an exterior appraisal, don't assume you are going to get it a day earlier - unless you want a sloppy appraisal. The same amount of blood, sweat and tears are going into the report.