Save to My Latticework unsave

Peltzman Effect
Peltzman Effect
Peltzman Effect
save0 saved view6.4K views
Share this with your network
Share this with your network
Overview

This phenomenon can explain why football players wearing helmets can be more prone to neck injuries; why pedestrians are at greater risk when ...

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Fortasse id optimum, sed ubi illud: Plus semper voluptatis? Quod equidem non reprehendo; Habent enim et bene longam et satis litigiosam disputationem. Esse enim quam vellet iniquus iustus poterat inpune. Duo Reges: constructio interrete. Quod quidem nobis non saepe contingit.

Tum Torquatus: Prorsus, inquit, assentior; Ergo, inquit, tibi Q. Eam tum adesse, cum dolor omnis absit;

Polemoni et iam ante Aristoteli ea prima visa sunt, quae paulo ante dixi. Quaero igitur, quo modo hae tantae commendationes a natura profectae subito a sapientia relictae sint. Estne, quaeso, inquam, sitienti in bibendo voluptas? Placet igitur tibi, Cato, cum res sumpseris non concessas, ex illis efficere, quod velis? Hunc vos beatum; Sed ad haec, nisi molestum est, habeo quae velim. Qui autem diffidet perpetuitati bonorum suorum, timeat necesse est, ne aliquando amissis illis sit miser. Alterum significari idem, ut si diceretur, officia media omnia aut pleraque servantem vivere. Quid, cum fictas fabulas, e quibus utilitas nulla elici potest, cum voluptate legimus? Graecis hoc modicum est: Leonidas, Epaminondas, tres aliqui aut quattuor;

Share this model with your network to be smarter, faster, together!
Actionable Takeaways
  • Expect less immediate positive impacts for new safety measures. 

Understanding ...

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nemo igitur esse beatus potest. Duo Reges: constructio interrete. Si longus, levis. Bork Intellegi quidem, ut propter aliam quampiam rem, verbi gratia propter voluptatem, nos amemus; Materiam vero rerum et copiam apud hos exilem, apud illos uberrimam reperiemus. Respondeat totidem verbis. Utrum igitur tibi litteram videor an totas paginas commovere? Stoici scilicet.

Ergo et avarus erit, sed finite, et adulter, verum habebit modum, et luxuriosus eodem modo. Eam si varietatem diceres, intellegerem, ut etiam non dicente te intellego; Non est ista, inquam, Piso, magna dissensio. Non igitur bene. Ergo hoc quidem apparet, nos ad agendum esse natos. Egone non intellego, quid sit don Graece, Latine voluptas? Expectoque quid ad id, quod quaerebam, respondeas. Ab his oratores, ab his imperatores ac rerum publicarum principes extiterunt. Illa argumenta propria videamus, cur omnia sint paria peccata. Si enim ad populum me vocas, eum. Quia voluptatem hanc esse sentiunt omnes, quam sensus accipiens movetur et iucunditate quadam perfunditur.

Ubi ut eam caperet aut quando? Utilitatis causa amicitia est quaesita. Sic consequentibus vestris sublatis prima tolluntur. Idque testamento cavebit is, qui nobis quasi oraculum ediderit nihil post mortem ad nos pertinere?

Limitations

Peltzman’s work was critiqued in a paper two years after its publication. Leon Robertson’s paper entitled A Critical Analysis of Peltzman’s ‘The Effects of Automobile Safety Regulation broke down a number of statistical problems with Peltzman’s work, explaining that: “The variables used in Peltzman's analysis were reviewed. It was concluded that some of them were arbitrarily chosen, that some were correlated, and that important factors were omitted. This may cause spurious and biased correlations. Peltzman's time series regression equations were reconstructed and found unstable, which makes them useless for predictions which are one basis for Peltzman's conclusions.” For those of you unfamiliar with academic discourse, them’s fighting words!

That said, the principle behind Peltzman’s work has persisted and evidence seems to demonstrate the effect does occur but generally does not negate all benefits of safety initiatives. A 2006 Dutch paper conducted an empirical study of motor vehicle safety and found that behaviour change related to the Peltzman Effect reduced less than 50% of the overall benefits. 

In Practice

Seat belts. 

This 1994 study of seat belt wearing explored behavioural adaptation by those starting to use seat belts and found that “beginning wearers (group iii) showed signs of continuing behavioral adaptation, in the form of increased speed and increased propensity for close following.”

Bike helmets. 

Cycling UK has argued against the compulsory use of helmets, explaining: “Cycle helmets have in any case not been shown to be an effective way to reduce cyclists’ injury risks. Indeed they might even be counter-productive, by encouraging drivers or cyclists to behave less cautiously, and/or by increasing the risks of neck and other injuries. By deterring people from cycling, they may also reduce the benefits that cyclists gain from ‘safety in numbers’.”

Booths Rule #2. 

Skydiving has become consistently safer over the last few decades thanks to a number of safety initiatives, some of them developed by skydiving enthusiast and inventor Bill Booth. However, Booth’s Rule #2 states, "the safer skydiving gear becomes, the more chances skydivers will take, in order to keep the fatality rate constant." Indeed, without the popularity of complex low to ground maneuvers and high speed canopies that allow for faster speeds, some claim that fatalities would be a fraction of what they were a few decades ago.

Build your latticework
This model will help you to:

d

Origins & Resources

Sam Peltzman, an economist at the University of Chicago, first described this effect in 1975 in relation to the car safety entitled The Effects of Automobile Safety Regulation. In the study, he argued that the increase of safety regulations was offset by people’s behaviour creating no change in highway deaths. The results of his report have been criticised (see Limitations above), though the effect named after the work persists. 

My Notes

    Nothing here yet. Join ModelThinkers and login to be the first to comment.
Already a ModelThinkers member? Please log in here.

Oops, That’s Members’ Only!

Fortunately, it only costs US$5/month to Join ModelThinkers and access everything so that you can rapidly discover, learn, and apply the world’s most powerful ideas.

ModelThinkers membership at a glance:

Small mark
UNLOCK EVERYTHING
Access all mental models and premium content.
Small mark
BUILD YOUR LATTICEWORK
Save models to your personal list.
Small mark
QUICKLY MEMORISE MODELS
Use our Learn function to embed models to memory
Small mark
PERSONALISE MODELS
Add your own notes and reminders.
Small mark
BUILD YOUR ‘EXTERNAL BRAIN’
Discover a new idea? Capture it by adding a new model.
Small mark
JOIN THE MT COMMUNITY
Rate models, comment and access exclusive events.

“Yeah, we hate pop ups too. But we wanted to let you know that, with ModelThinkers, we’re making it easier for you to adapt, innovate and create value. We hope you’ll join us and the growing community of ModelThinkers today.”

Arun Pradhan & Shai Desai
CoFounders, ModelThinkers.

You Might Also Like:

- Actionable summaries of the world's most powerful ideas.