## Saturday, October 6, 2012

### 18 Days with Sherlock – Day 15 – Keep an Open Mind

Previously we talked about Going With the Obvious explanation for any specific fact, however, you also have to keep an open mind because the obvious answer may not be the right one in every case. You have to then come up with alternate scenarios and you do that by Analyzing the Data.

Here is a simple example: Let's say you are looking at the 1870 census and you see John Q. Doe, age 32 living with Mary Jane Doe, age 28. There is a child listed, William D. Doe, age 11. The obvious explanation is that John and Mary are married and William is their son. However, since relationships and marital statuses are not recorded on the 1870 census it is just an assumption. Other explanations could exist. We need to investigate this further so we go back to the 1860 census.

You find John Q. Doe, age 22 but this time he is listed with Hannah Doe, age 20 and William age 1. Next door you notice a James Doe, age 50, and in his household you see a Mary Jane Doe, age 18. Time to come up with an alternative scenario. It looks as though John was married to Hannah and they are the parents of William. Hannah died before the 1870 census and James' sister Mary Jane moved in with him to help him with his small child. Is this the only possible explanation? No, but at this point this has become the most obvious and that will be our new Working Hypothesis. We then investigate further to see if this theory pans out.

We go back to the 1850 census and we find James Doe, age 40, John Q. Doe, age 12 and Mary Jane Doe age 8 living in his household. So far so good. We still need to do more research. We find John Q. Doe and Miss Hannah Jones' marriage certificate dated 01 Jan 1858. You also find a marriage certificate for Miss Mary Jane Doe and David White dated 04 Apr 1875. Everything fits into your current hypothesis. You still have to investigate further to find every available document but it looks like we are on the right track.

Just a little side note, I hope you noticed that we were working backward in time. I have mentioned on several blog posts that going backward in time (going from the known to the unknown) is a more effective research technique than trying to work forward in time.

“Circumstantial evidence is a very tricky thing. It may seem to point very straight to one thing, but if you shift your own point of view a little, you may find it pointing in an equally uncompromising manner to something entirely different.” [Holmes to Watson, The Boscombe Valley Mystery]
“There is nothing more deceptive than an obvious fact.” [Holmes to Watson, The Boscombe Valley Mystery]