Johnnie Walker a long while back made a throwaway comment when he was commenting on his own Search Analogy;

I know of Police Services who ban purposeful wandering by their search volunteers. Yes, you read that right. Not insist on it. Ban it!
[Read it here if you don't believe he wrote it...]

I have endeavoured since then to get more information about this, but as yet, it remains [to me, I hasten to add] an unsubstantiated rumour.

It comes, apparently, from a conversation had at the UKLSI Search Controllers Course. I’m afraid I’m being elusive about it because the best thing for a misper is a good working relationship between a PolSA and the search team. I do not want to do anything to jeopardise this so won’t be going any further into what team, what was said or so forth. [Although maybe this is a job for a senior representative of ALSAR to work with the police nationally!]

I’m hopeful it is all a misunderstanding, but in case it isn’t, I am writing a defence of the technique in order to give more information to make an informed decision on its usefulness!

As you all know purposeful wandering is the search technique whereby a foot searcher, searching their “search strip” meanders through the strip searching certain bits. The big clue is in the term “purposeful”. Each searcher looks at their search strip. Some sections of it are clearly visible and do not contain the misper. I’m hinting at all those open bits – the grass, the ground between the trees! However, some bits of their search strip are not clearly visible and need closer attention.

The searcher, then, wanders this way and that – searching the bushes, tree stumps and so on; where a misper might be hidden!

My first comment on hearing the rumour was – so if I see what looks like a foot, should I go over and check it or just keep to my straight line? Essentially this is what purposeful wandering is – checking the bits that are not immediately visible.

Now if this wasn’t enough to persuade you that this is a useful technique, I can go even further. The Probability of Detection (POD) of a search resource is based upon it’s track length – how far it travelled within the search area. The shortest distance between two points is a straight line – start wandering from side to side searching bits that need a closer look, not only to you prioritise those areas and make sure they are searched, but you also travel further, spend more time searching and increase your chances of finding the misper!

Without knowing more about the issue, I am only speculating, but one possible reason for insisting on straight lines is a misunderstanding of the maths of search theory. There is a search calculation – based upon perfectly straight search lines – that gives a higher POD for the same effort. However, this is based upon almost perfect [flat, calm] sea conditions – totally unlike any piece of land you will ever get to search! There is no alternative then than putting in more effort to achieve higher PODs!

Hopefully, this is enough of a starting point to persuade anyone involved that purposeful wandering is an essential tool for foot search and straight lines are most definitely OUT!