Coverage as a word is often used to describe how much of a search area or sector has been searched. This is wrong.
Coverage has a specific mathematical definition in search theory. It refers to the Area Effectively Swept divided by the Area of the Search Sector. This figure is then used in Koopman’s Exponential Detection Function to calculate POD.
The probability density is found by dividing the Probability of Area (POA) by the size of the search area or sector.
This gives you an idea of the likelihood that the missing person or object is in an area of the same size in two different search sectors. It is an extremely important concept to understand in managing a search. The higher the Pden, the better the chances of finding the misper.
I have decided to start an online SAR dictionary that I will add to every week. Hopefully it will help those looking for more information and/or definitions of various SAR terms.
So far I have added;
Probability of Detection (POD)
and
More will be added week on week.
Probability of Success is the likelihood of finding the misper or search object given the search area and search resource. It is calculated as below;
It is the role of the Search Management Team to maximise the POS of the search. [Find the missing person or object as quickly as possible!]
This does not mean maximising the POD (Probability of Detection) of the search effort. In fact, in many cases maximising POD will reduce the POS of the search!
Probability of Detection refers to the likelihood of a search resource finding the object they are searching for if it was in the area they were searching.
Thanks to Koester, Cooper, Frost and Robe’s 2004 study we can now safely say that it is impossible to subjectively estimate POD. No more should we hear supposed Search Managers asking how many clues out of ten would we have found!
In order to calculate POD you need to calculate total track length, know the “sweep width” of the search resource, the size of the area being searched and use “Koopman’s Exponential Detection Function”.