When do we know if something is a problem?

I’ve written about this before, both when discussing the implications of an unidentified submarine in the Stockholm waters (described in Should we in Sweden be surprised when we learn that there are foreign submarines in the Stockholm archipelago? Hardly!) and when I try to decide if my bike route to work is dangerous or not (two posts: (i) Risky business on land and (ii) One accident doesn’t mean thing is risky).

Now, a couple of days ago I witnessed the result of one more bike accident at the very spot described before. This time I estimate that the accident was a result of the sharp turns in combination with the curb stones collecting water that had frozen during the night, i.e., the physical layout created a hazardous condition.

So, the question is: I have a record of a very low number of incidents (in the submarine case one incident, and in the bike lane case two incidents), can I judge (calculate) the likelihood of this being evidence of a problem?

Note: In these cases I have a record of the incidents and the number of incidents and conditions for each incident are known. I don’t base it on hearsay or for example on newspaper articles talking about many biking accidents (which could be ten persons describing what could be the same accident). For the submarine incident this means that I trust the description the Swedish Armed Forces gave regarding some basic aspect of the incidents.

Judging if the incidents are a one-time event or evidence of a bigger problem came in the submarine case down to estimating how likely it is that we observe a submarine if it is in the area. In the biking case observing is not a problem, i.e., it is about how often we are on the scene.

For being able to calculate total number of bike accidents we need more information. In short we need to estimate how often I’m on site and what that mean.

Calculation example: Rush-hour accidents (in one intersection)
No of observed incidents: 2

Observation time per day [minutes]: 1

Observations per week [per week]: 9
Average incident observation window [min] (duration of accident): 10

Total period [years]: 1.5

Weeks per year [weeks]: 46
Days per week [days]: 5
Hours per day, rush-hour [hours]: 2

=> Total period [minutes]: 41400

=> Total observation time [minutes]: 6831
=> Observation percentage: 17%

Estimated no of incidents in total (from observation percentage): 12

Bikers per minute (during rush-hour): 2

=> Sample size, calculated [no of bikers]: 13662

=> Incident per observed biker: 0.01%

Statistical error margin (given sample size and a 95% confidence and normal distribution): 0.02%
=> Number of incidents: 0.01% ±0.02%, i.e., between -5* and 29

*) we cannot have negative number of accidents, i.e., assumption about normal is distribution wrong (wrong left tail). Two incidents are observed, i.e., these two could statistically be the only two

=>                                                   

Minimum number of incidents (the observed ones): 2

Expected number of incidents: 12

Maximum number of incidents (given stat. error margin): 29

Per year

Minimum number of incidents: 1

Expected number of incidents: 8

Maximum number of incidents: 19

But if this 1 to 18 accidents per year in one intersection a problem? Is it too often? If we put that question in a safety (risk) perspective we also need to know the consequence of an incident. I estimate that one out 20 incidents lead to serious injuries. The probability for exactly N injuries is then described by the binomial distribution. Given this frequency, the expected number of incidents and the binomial distribution we can calculate the probability for exactly one, two, three… serious accidents per year. Then we can calculate a FN-curve for each of the three number incidents above (1, 8 and 19 per year) where N is the number of persons seriously injured per year in this intersection.

FN-curve describing the probability for N or more serious injured persons per year if there is one accident per year (filled circle); eight accidents per year (circle); and 19 accidents per year (squares). (C) Hans Liwång 2016.

However, to my knowledge there are no FN-criteria for one intersection, so we still do not know if this is a problem or not. I however note that the probability for at least one seriously injured person per year is close to one which sounds high for one insignificant intersection (I pass at least 40 of that size per day).

The most crucial figure in the calculation above is the average duration of an incident. Note also that if my wife, who also twice a day pass the same spot on her bike, tell me that she had an accident on this spot I could not include that information because it is outside my sample.

I promise to get back with a maritime case complementing the FN-curve I did when describing that the risk for refugees in the Mediterranean so high it is intolerable.

ROV carrying explosives near Nord Stream pipeline

I've talked about tension and how for example the tension in and above the Baltic Sea increases and therefore also the probability of security incidents increases.

On November 7 (2015) an unmanned remotely operated vehicle (ROV) was found on the sea bed in the Baltic. It was found on international water, but within the Swedish economic zone. What makes this story extra juicy is that:
(1) the ROV was found not far from the gas pipeline Nord Stream going from Russia to Germany, and
(2) the ROV is carrying explosives.

This type of ROVs are often used in mine clearing operations (of new as well as old mines). In such operations the mine is first localized with sensor from afar and the detonated under controlled circumstances with dispensable ROVs like this one (used by many nations).

Unfortunately the Baltic is full of old WWII mines and unexploded ammunitions. Clearing mines in the Baltic (especially in the eastern part) is a long going tradition since Estonia, Latvia and Lithuania became independent states in the beginning of the nineties and the Swedish Navy has taken part at least since the mid nineties as an exercise with an important result. However, the exercise became more political as a result of the Ukraine crisis even though clearing WWII mines has only friendly implications.

The relative large extent of mine clearing over a long period of time in the Baltic makes it very possible that the now found ROV is a left over from such operations. Therefore, the most likely explanation is that the ROV is a result of peaceful intentions. However, I've seen discussion on the internet trying to make it out to be something else. The point of such discussions can be questioned!

Swedish boarders has been violated at least 42 times over the last five years

Based on a request from the Swedish news paper Dagens Nyheter  the Swedish Department of Defence has released a list of the documented violations of Swedish borders in the air and at sea for the years 2011 to 2014. In total the list contains 42 incidents and 16 countries (out of which 12 are NATO countries).

The list is based on information provided by the Swedish Armed Forces and new a praxis in force since October first 2015 makes the information available to the public. This new praxis is mostly a result of political needs to put defense issues on the agenda.

The amount of violations has increased from three in 2011 to twelve in 2014 (not counting the submarine in the Stockholm Archipelago in October 2014) and so far eleven times in 2015.

Personally I don't want to put too much focus on the violations because every serious nation will train their forces and easiest way to do this is from your country and outwards, i.e. towards your neighbors. During such training an over eager pilot can easily turn away to late even though there is no aggression involved.

The highest number of violations are performed by the US, seven in five years. Russia only six during the same period. This in itself is nothing to get all fired up about and also Sweden manages to do the same to our neighbors. However, two things worries me:
- Russia does not acknowledge their mistakes which could lead to problems if there was a more serious incident; and
- the increased numbers of incidents is a proof of more activity and probably also more tension over the Baltic Sea.

With more activity (and tension) comes an increase in the probability of something going wrong or being interpreted the wrong way which could lead to consequences, i.e. there is an increase in security risk on and above the Baltic Sea.

Now easy to download!

The article Ship security challenges in high-risk areas: manageable or insurmountable? by Österman, Sörenson and myself and published in the WMU Journal of Maritime Affairs is now easy to download from the journal's webpage:

Liwång, H., Sörenson, K., Österman, C. (2015). Ship security challenges inhigh-risk areas: manageable or insurmountable? WMU Journal of Maritime Affairs.14:2. pp 201-217.

Safe at port or safer at sea?

Land is dangerous 1(4)
Personally I as a captain (of my small boat) feel the safest when the boat is away from land and the less control I have over the boat (as a result of for example bad weather) the further away I want to be (but a nautical mile or two is often for me enough). My respect for proximity to land stems form that I have seen the problems that rock-ship interactions can have, but also because I know how the effects of bad weather can be turned in to dangerous forces by the closeness to land such as when shallow water makes a seemingly small wave turn into a wall of water or when high wind speeds are turned into erratic gusts by land formations.

Land is safe 1(1)
At the same time I see the logic in rules and regulations that define port as the safest place to be. This is exemplified in regulations such as:
- the safe return to port concept for passenger ships (because a port is the only place where many people can debark safely), or
- when some types of work are only allowed to be performed if the ships is at port.

Land is dangerous 2(4)
My research clearly show another dangerous aspects of land. Ships are the most susceptible to many security threats in ports or close to land as a result of low speeds and high density of ships. Civilian examples of this include piracy in the Malacca Straits and off Nigeria and military examples include the suicide bombing attacks performed on naval ships (Hans Liwång, Survivability of an ocean patrol vessel – Analysis approach and uncertainty treatment, Marine Structures, Volume 43, October 2015, Pages 1-21) of which the attack on USS Cole probably is the most know example.

Land is dangerous 3(4)
Another example of safe at sea is tsunamis were you at port or even on land potentially is a sitting duck. However, at sea a potentially devastating tsunami may raise the sea level but can pass by unnoticed.

Land is dangerous 4(4)

Almost all (>90%) personal injuries onboard ships in the Swedish statistics from the years 1995-2010 happened in the harbor area and about 60% when a ship hit a man-made structure above water (kay, dock, bridge).

Consequently, I see land as a dangerous thing for boats. It is a 4-to-1 victory!

But then reality show me that it isn’t that simple
The container ship El Faro sunk east of theBahamas October 1 2015 after losing propulsion while attempting to get away from the hurricane Joaquin along the ship's route from Jacksonville to Puerto Rico. All reports indicate that the 33 persons on board died in the accident. Loss of power makes the waves much more difficult to handle which in this case probably led to the reported list and water intrusion through an open hatch. Therefore, in this accident being at sea introduced several uncertainties which this time interacted in such a way that the ship sunk.

Consequently I have to update my statement from above about land being dangerous:

At sea a ship is in its right element and even if something goes wrong you most often have the time and possibility to fix it before it gets dangerous. However, at sea the uncertainties are high and how and when depends on many aspects.

The land it self introduces several new potential hazards, however the situation or consequences are generally more controllable or predictable.

So if you like predictability stay close to land, but if you really want to use the boats capabilities be at sea.

Risk management when it goes wrong: artificial sounds on (electric)cars

All over the world (for example USA, EU and Japan) and there are popping up laws banning (or plans for banning) cars that does not make a sound. This as a result of the low level of noise from electric cars at low speeds.

The argument is that if the car doesn’t make a sound you will not look for it and therefore step out in front of it, but also that sound is important for blind persons. The speeds discussed are low, i.e. “parking lot speeds”, at higher speeds all cars make a sound.

Today we have a society where cars are all over the place; this has not always been the case and will hopefully not be the case for ever. Putting warning sounds on cars can only help in situations where cars are the only danger. In all other situations you still need to be careful.

Therefore, banning quiet cars is based on a technocratic view on safety and a narrow understanding of our world (it is not a robust solution). A more robust solution is to teach persons to use appropriate carefulness when moving around. If you can, look where you are going; if you can, listen for sounds that could mean problem; if you can, smell for smells that could hinder your activity and so on and then use the information gained to guide your actions (like lowering your speed if you lack relevant information). This robust solution will work for interactions with cars (silent or not), bikes (silent or not), lions (silent or not) and so on…

At parking lot speed I for one have no problem with stopping for a walking person (blind or not) as long as he or she is not thrown out in front of my car. However, as I biker I have a problem with people with headphones that, without looking, suddenly step out into the bike lane (because they also think, as many legislators do, that everything dangerous sounds a lot).

Do not try to fix a behavioral problem with a technical solution and I am hoping for a quieter future!

Insightfully written about assessing (security) risks

I too seldom push for work by others, but today it is easy. I had this summer the pleasure of reading Terje Avens article “On the allegations that small risks are treated out of proportion to their importance” in Reliability Engineering & System Safety (Volume 140, August 2015). I the article Aven take his starting point from two risk examples, one introduced by Kahneman in “Thinking fast and slow” and one by Joakim Hammerlin in the book “Terrorindustrien”, both examples deals with risks from terrorists. Aven’s point is that when assessing a terror risk there is no right answer. Therefore are terms like under or over estimation irrelevant (as well as objective risk). A terror risk cannot be compared to lotto or other well defined systems, because in such systems there is a right answer.

An insightful article.

This doesn’t mean that we should stop assessing terror risks, but we should understand the difference between types of risk management situations and also always include/assess uncertainties. But don't take my word for it, read Aven’s article instead:

Aven, T. (2015). On the allegations that small risks are treated out of proportion to their importance, Reliability Engineering & System Safety, Volume 140 (pp 116-121).

http://dx.doi.org/10.1016/j.ress.2015.04.001.