Posts Tagged ‘Lost Person Behavior’

Calculating Probability Density Distribution for Missing Person Search

January 26th, 2010

The first of the four elements of the optimal search problem is having a probability density distribution (predicting the likelihood that an object is in any particular search area or region.)

To achieve this during a Maritime Search and Rescue Incident one takes into account the accuracy of the initial location report, the current, wind and so on. Computer models can then accurately map the likelihood of the boat (or whatever search object is being sought) being in any particular area.

However, the variables for a vulnerable missing person search are not yet known with any particular accuracy. They may choose any direction; may stay on paths or tracks, or depart from them; camp or find shelter; try to cross rivers; go uphill or down; and so on and so on.

Computer models of missing person behaviour then are not as useful or accurate as Maritime models. This does not, however, mean that we cannot come up with useful probability density distributions. Take a quick glance at Robert Koester’s, Lost Person Behavior book to see that the world SAR community has over 50,000 incidents’ data to draw upon.

From this we can predict the likelihood a given misper will travel a certain distance from their initial location and misper “type” or “category”. This is sufficient to draw a couple of circles on a map and calculate probability density’s for concentric regions on a map. It is a small step from this to calculate actual Probability of Areas (POAs) for specific search sectors.

Other potential methods for calculating probability density distributions include the consensus method – allowing for subjective calculation based upon search planners’ experience, the individual misper intelligence and the actual search terrain limitations.

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Should we be “Clearing” areas in vulnerable missing person search?

January 15th, 2010

Missing Person Behaviour Presentation to Berkshire Search and Rescue Dogs

Berkshire Search and Rescue Dogs kindly asked me along to give a presentation on missing person behaviour on Tuesday night.

As part of this presentation I briefly discussed how survivability data helps prove search is an emergency. And, of course, if you accept that time is a critical feature in your search plan, you have to consider the possibility that “clearing” search areas is not an effective use of search resources in many cases.

Here is the PowerPoint presentation -
Missing Person Behaviour Presentation For Lowland Search Dogs

I’d like to thank BSARD for both their invitation and their warm welcome. I’d also like to thank Jo Joslyn for the lovely letter of thanks.

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Evidence Based Practice in Search

November 30th, 2009

UKLSI Conference Presentation 2008

I was reminded of this presentation I did last year at the UKLSI Conference, held within Sussex by Sussar and Sussex Police, when hearing of someone reading Koester’s explanation of search theory in his book, Lost Person Behavior. I had not yet received my copy, unlike a certain Wilsar Search Manager, but was glad to find a lot of similarities with my presentation.

It can be found at
http://www.re-search.org.uk/evidence_based_practice_in_search_UKLSI_08.ppt

I can’t remember what deliberate mistakes [cock-ups] we found in it, but as I’ve said before – they help to see who is lifting the material straight from slides without double-checking it!

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Search exercise planners handbook – Part Five

November 18th, 2009

Picking your search exercise’s SCENARIO

One of the other things that often let’s down ALSAR search exercises is their scenarios. This is despite the fact that many search exercise planners and training officers spend a large amount of time coming up with these fantastic scenarios [or more accurately because they do!]

Classic examples of this include some probationary ALSAR Units’ assessment exercises such as the man who abducted his two children and is now deemed suicidal. Probably thought up to give a definate IPP and three mispers to find, the scenario is unrealistic. How often does your Unit get these calls? Does your local police really believe you are an appropriate resource to use for locating abducted children anyway? [Personally I'd have failed the Unit for not thinking about or mentioning this during the briefing - but I suppose if you are set this for your assessment, with police and assessors looking on you are stuck with it!]

So what scenario should you use? Guess what, you need to train for what we do. So go back to your Unit’s callout stats – find out what you are generally used for and start thinking about that as a scenario. Over two thirds of ALSAR callouts are for mispers with Dementia and Despondents. So over two thirds of your search training scenarios should be for these – unless your local stats tell you something different. This might happen; a coastal Unit may be called for missing children on holiday more – I don’t know, your Unit should!

Once you have your misper type, you then need to turn to your misper stats. Get out your well-thumbed copy of Koester’s Lost Person Behavior and find out what this type of misper does. How far they travel? Where they are found? How far from the track? In what sorts of environment and position?

This should form the basis of your planning for where the misper will be during the exercise. Whilst it is tempting to position the misper to be found at the “right” time when the exercise should end, try to avoid this – it will skew searchers expectations of where missing persons are found. Rather select an appropriate location according to the stats – 30% of the time in your exercises they will be close in and found quickly for instance [or hopefully they will], 20% of the time they will be found by R&P outside the hub and so on.

You can always plan an extra activity to follow the exercise if it finishes too early. However, most ALSAR Units do not leave enough time to properly de-brief and feedback following exercises anyway. UKLSI allows one and an half to two hours to de-brief the Team Leaders after their assessment exercise which last three hours – this is on top of their assessment feedback; just time for them to share what they have learnt from the exercise. This gives you an idea of how much can be learnt from this process and how little it is done after Unit exercises.

So pick your scenarios with care and attention to detail. They can make or break the exercise and its benefits to your Unit.

Return to Search Exercise Planners Handbook Index

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Emergency Response & Search & Rescue by Gary Foo

November 13th, 2009

This new book seems to have aroused a lot of interest, certainly here in the UK, but also abroad too. It seemed appropriate then to write a quick review of the book.

The book covers a vast amount of ground in its 300 plus pages. It starts with a round-up of the different SAR disciplines, explaining briefly a bit about them and how they differ from each other then adds some detail on SAR in the UK.

I especially enjoyed a section on possessiveness and parochialism in SAR and totally agree when Gary writes;

Don’t get me wrong. Those teams who may be well intended and benevolent but dangerous in their presence are also a problem. If their attitude or fitness or competence lets down the mission objective – and I have seen that too – then you also need to be careful

I would probably go further and say that we need to do everything we can to weed out individuals and organisations who want to “play” at SAR without the appropriate levels of competence or with the wrong attitude.

Gary’s book then looks at the International SAR scene and disaster and major incident management. This is drawn from both national and international sources and contains a wide variety of information.

Preparation for search is covered next; with information on callout systems and alerts. It also contains detail on SAR command, team roles and briefing and de-briefing. SOPs, clothing and uniform, equipment and packing, SAR vehicles, communication and logistic in this wide ranging chapter.

Gary then writes about Field Survival & Navigation before moving onto the chapter I was most interested in – Search and the Missing Person/s.

Gary starts by introducing the Foo’s Five Missing and Lost Categories, before moving onto Ground SAR profiling and Lost Person Behaviour. Much of this draws heavily on Koester’s book Lost Person Behavior, with some reference to earlier studies in both the US and UK.

In my view Gary then skirts very quickly over the mathematics of search theory before looking at search methods. Unfortunately I did find some errors in this first edition of the book in this section, some of which were disappointing, but Gary has said that the second edition will address any errors found.

The section on search patterns looks mainly at maritime and aerial search, with a small nod towards ground and land SAR, followed by a very brief section on vision, searching and seeing.

Tracking, Search Dogs and Mounted SAR, Mountain and Motorbikes for search are all covered briefly before Gary writes about Rescue and Advanced Skills in the next chapter including heights, ropes and knots, water and flood work and collapsed building SAR work.

Finally Gary covers SAR medicine including Foo’s Triage System alongside other more traditional medical issues and detail and keeping fit between SAR operations.

Overall, the book covers a lot; perhaps too much. I would certainly liked to have read more on each of the different aspects of SAR and in more detail but maybe this introductory book was designed to cover everything briefly – with more detail in the later books.

However, when any book refers to me as an “authority on search in the UK” I can’t slate it too badly, can I?

Buy the book via Amazon.

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