Sources of Data [Sept. 11, 2012, 6:28 a.m.]
Please list any and all sources of data you can think of about road injury.
Newspapers can be:
- a data source (because they will publish information on individual collisions) as well as
- reporting on other data sources.
So you may list newspaper (in the sense of an individual report) but then think about the actual data they might use for other articles.
You may like to visit the Interesting Injury Headline Database to give yourself some ideas.
Now that you have considered this, here is a list of common sources:
Official Sources (from the Government)
1. "STATs19" - This is the name given to the database of Police-collected information on road collisions. In theory, if any vehicle (motorised or not) is involved in a collision on the public highway that results in an injury this event should be reported to the police. This is the "definitive" source of information on road injury in Great Britain. Whether it is perfect or not, the Government's understanding of injury, how we compare with other countries, how injuries change over time and how different parts of Great Britain compare with each other is all based on these data. Because of it's importance in policy and performance, we will say a little more about these data later on.
2. HES (Hospital Episode Statistics) - If an injury is serious enough to warrant admission to hospital, it will be recorded in these data. There is a degree of fine detail on the cause of the injury (road user type) and various demographics but nothing about the geographical location of the collision.
3. Ambulance Records / A&E records - There are data available from these services which provides yet another version of what is happening on our roads.
4. Fire and Rescue Information - Some data will be recorded on the collisions to which F&R Services are called.
5. Coroners Courts, and Death Registrations - There are number of other places where information about fatal road injuries get recorded.
Para-Official Sources
1. Insurance company records - One of the headlines in the database referred to a press release given by the company "Sheila's Wheels". This is another version of what happens on our roads.
2. Fleet managers records - Health and Safety Legislation will encourage fleet managers to be more careful in recording collisions involving their employees driving on business.
Other sources
1. Surveys - There are numerous large government surveys, such as the ALSPAC survey (carried out in Avon) and the Health Survey for England which ask people questions about their involvement in road collisions. Some of these surveys can be very informal and badly designed.
Information about road behaviours
There is also a wealth of information to tell us what is going on around Britain's roads. This includes:
- Records of offences (such as speeding and drink driving - both of these are mentioned in the Headline database - neither concern injury directly)
- Records of road usage - such as the number of vehicles registered, the amount of traffic, the speed of traffic, the characteristics of vehicles
Please now consider a few questions about the police-collected "STATs19" data (the definitive dataset):
1. What is the main purpose for the police activity that leads them to fill in a long form with information about a collision?
You may assume that the primary purpose is to inform the injury prevention effort. However this is not the main purpose. It is a useful by-product of police attendance at a collision that we get all this information, but we do need that it is just a by-product. There is actually an "On The Spot" study, carried out around Loughborough involving the Transport Research Laboratory in which detailed collision investigation teams visit scenes to collect prevention information.
The main purpose for police involvement is to determine whether an offence has been committed. There is a considerable amount of "first aid": warning other road users of a crash site so that there aren't further collisions, keeping the scene safe for any other emergency services and dealing with distraught people and so on.
2. Why should we be cautious when interpreting the data from such police-collected forms?
Many if not all "official" statistics are the byproduct of a process. The involvement of police at the scene of a road collision (or the involvement of police in a station if a collision is reported there) is not primarily geared towards injury prevention.
If a person works with a prosecution mentality, all conclusions have to be drawn "beyond reasonable doubt". It is hard, without proper accident investigation procedures, to determine the speed of vehicles prior to a crash. So it is entirely reasonable to expect the forms to be filled in with some caution. Important causal factors, such as Excess speed may not be entered. This is not because excess speed wasn't a factor, but because it couldn't be determined beyond reasonable dount in a collision involving minor injuries only that excess speed was a factor. So when interpreting these data, we need to be mindful of the filters that were applied when the forms were completed.
3. What are the two conditions required in order for an event to appear in the database?
(a) the collision participants need to tell the police
(b) the police need to agree that an injury has resulted from a collision involving a vehicle on a public highway.
4. A number of possible reasons are listed below which might either result in someone not informing the police, or the police not recording an injury as a result of a road collision. Which is NOT a reason that prevents a collision being recorded and is fact a reason for a non-injury collision to be recorded?
a) An uninsured driver would prefer not to inform the police of a collision.
Estimates vary, but there are suggestions that 1 in 10 motorists are not insured. If you could avoid it, you'd probably prefer not to have a long discussion with a police officer about a road collision if you were uninsured.
b) Someone does not realise that crashes involving bicycles have to be reported. All collisions involving a vehicle, motorised or not, which result in injury should be reported.
The "rules" regarding the way data should be reported an exactly how it should be recorded are rather complex. As road users, we are rarely involved in a collision. Many police officers are only required to attend a small number of road collisions every year. It's really asking for train-spotter / stamp collector mentality (who said statistician mentality) to understand all these rules in all their fine detail. So it may be that with the best of intentions, not every detail of every eligible collision gets recorded entirely accurately. If you cut yourself having come off a bicycle when hitting the curb, are you sure you'd expect it to be reported and recorded?
c) It does not appear that anyone is injured - and few of us realise the official definition of Injury.
A very long standing criticism of the STATs19 data are that "injury" is defined in a very strange way, and is not assessed by a medically trained person. So, with the best of intentions, the precise severity of a collision may not be recorded accurately. This could result in a "slight" injury collision not being recorded at all, or a "serious" injury collision being recorded as a "slight" injury.
d) A driver in a very minor collision in which no-one else is injured decides they can "invent" an injury in order claim compensation.
This is one example where you might have records of collisions where you should not.
We need to make a few more points about:
(a) The definitive dataset (the police collected "STATs19" data)
(b) Surveys
(c) Offences
(d) Vehicle manufacture information