This is the fifth edition of the book and the first done without direct involvement of Heinrich, since it was done and published nearly 10 years after Heinrich had died. The book is heavily reworked from the second edition that I had read before, but it still includes some few passages that are copied literally from older versions. And to be honest, it’s awkward to have a 40 or 50 years old text between the other, relatively modern, texts (even though the readers who are unfamiliar with previous versions may not notice it - I did and I found it strange).
Now I haven’t read the 1950 and 1959 versions of the book, but it appears that Petersen (who seems to be the main writer/editor here) and Roos take a departure from some of Heinrich’s original thoughts and while keeping the title and some of the structure and thoughts as the basis they primarily aim to “look at how the principles have stood up to these exacting tests” and add a lot of newer knowledge along the way. One of the author’s aims is to give safety professionals a good professional knowledge, because “the person who has a sound knowledge of the principles… is well equipped to deal constructively with… all exposures” (something that sounds as an argument for generalist safety expertise).
Let’s have a look at the contents. This edition is split up in four parts. Part I covers the basis and philosophy of accident prevention. Part II deals with (a?) accident prevention method. Part III takes on some special subjects and Part IV contains the appendices.
The first chapter lays down the basic philosophy by introducing the author’s idea of accident prevention which includes both prevention and correction. While worker failure still is a central theme, there is attention for both an immediate approach and a long term approach, including controlling acts and environment and working on things like competence. Also Pedersen & co see the same improvement principles for safety and production.
A number of rather simple models is introduced, including Kepner Tregoe (p.9) and MORT (p.10/11) and we are presented with the statement that “errors are inevitable” - compare that to earlier work of Heinrich. This is, by the way, the first of the 6 criteria of MORT. Good stuff. The MORT performance cycle is basically a (less complete) variation on the famous Plan - Do - Check - Act of Shewart/Deming. Page 12 presents a combination of various models. What I like in this model is the inclusion of principles and beliefs in the most basic level - so they do include safety culture, only they didn’t know that concept at the time yet, I guess.
Chapter 2 is basically a critical evaluation of Heinrich’s 10 axioms. And as we will see, safety science has in the meantime come a longer way than the original axioms which are heavily revised at places. The most striking example of this is probably the updated domino sequence presented on p.25. The one we see here, is the commonly current day used one by Frank E. Bird jr. including Basic Causes and Lack Of Control as the most right dominos instead of Fault of Person and Social Environment as Heinrich originally proposed. It’s also Bird who is quoted at length and discusses critically the (former) focus on direct causes.
The book presents several other variations on the dominos, including one by Edward Adams (p.30). He has an odd (IMHO wrong) understanding of the terms operational and tactical (the wrong way around) but worse in his version is the forced way in which he tries to plot organizational levels into the domino sequence. His detailed descriptions of elements in the dominos, however, are valuable and the fact that he includes “personality of the organization” (again, culture without calling it that) at the most basic causal level is very good. Quote: “Management structure is a reflection of the beliefs, objectives and standards of the key decision makers of the organization”.
Weaver’s variation on the dominos (p.31) is even less successful. He again includes terms like “Fault of person” and “Heredity”, pointing at the person and the question about “whether” suggests a lot towards counterfactual reasoning.
P.33 presents a model by Zabetakis that gives an interesting perspective. Strong element is that Zabetakis more or less equates the direct cause of an accident with an unplanned release of energy; a good thought and useful shortcut in many occasions. Disadvantages are that the model is a bit too complex to keep easily in your mind and the connection between management factors and other causes is not clearly described, although the model does include plenty of management factors. Another model is the Stair Step Model (p.38/39). The idea of using tolerance boundaries appeals a lot to me, but regrettably the model itself is too complex to explain and therefore nearly useless in practice.
One further expansion on Heinrich’s work is Multiple Causation. Heinrich’s original understanding was fairly linear, but p.36 takes on critically this “narrow interpretation”. And justly so; the dominos, linear and singular as the metaphor may be, need not be a limitation to multi-causation. Also root causes are discussed here.
The chapter continues with a number of other models, including the Motivation/Reward model (p.44) that may be useful to explain behaviour (even though there are even better ones, like the Theory of Reasoned Action of Ajzen & Fishbein, but then this was published in the late 1970s and may not yet have reached Petersen…). The Petersen accident model (p.49) looks a bit multi-domino-ish. Rather strong feature is the human part here regarding the time of writing - James Reason’s seminal work still had to come, mind you. Pretty weak, however, is the sidestep with ‘System Failures’ none of which can be the direct cause of an accident, but the diagram seems to suggest this.
Another theoretically sound model appears to be the Firenze model. Disadvantage is that the graphic representation is near impossible to explain. An interesting thought here is that “accident causation involves consideration of as many variables that affect the system as possible…” something that hints a bit of FRAM, many years later…
The Ball model (p.54) states that “all accidents are caused by hazards” something which I disagree with. A hazard is a necessary condition for an accident, but since a hazard also is a consequence of something desired (traveling by train with high speed, having a drink on your balcony, hot coffee) it should rather be regarded as part of the context than as a cause.
The final model presented is the Surrey model (p.54/55) which is very handy and logic, but alas cursed with an (IMHO) unpractical graphic representation.
The authors conclude this lengthy discussion of various models with a piece of sheer wisdom (if you ask me): “we believe there is no single best model”. Amen to that!
Section 3 of the second chapter takes on the subject about humans and machines. There is a very interesting discussion on the discrepancy of “humans cause” and countermeasures aimed at machines. A really intelligent observation, and well handled. There’s also a discussion of how Heinrich came to his 88% of human causes. Regrettably after this rather intelligent introduction there is a (for me) rather stunning twist: the authors lock in on human failure and even criticize the OSHA law that addresses mainly conditions (I would think, by the way, that the law takes on hazards and countermeasures, not as much causes). A very strange passage in this book.
The fourth section discusses the pyramid. The book states that the 300 : 29 : 1 ratio originally was viewed as an opportunity, and I think that’s an excellent point of departure. After this we’ll get the Bird update of the pyramid (1 : 10 : 30 : 600) and a discussion of the confusion about the ratios and a sensible conclusion is that “it does not mean that these ratios apply to all situations…”, “…the triangle for electricity is different from the one for handling material…” and “…common sense dictates totally different relationships in different types of work” (all p.64). All of which is very much in line with my thoughts about the Common Cause Hypothesis (which doesn’t get called this way in this book either). I think, however, that Petersen et. al. screw up a bit with their understanding of the phrase ‘frequency’, addressing only minor injury and not near misses and conditions/acts that would fit in the same CCH-group.
Most of the other Heinrich axioms come out rather well from the discussion and update. Petersen and his team agree with the responsibility for management and say even rather boldly: “In safety we’ve gotten into the ludicrous position of pleading for management support instead of advising how management can better direct the safety effort to attain its specified goals”. Keywords: communication, responsibility, authority and accountability! Bird appears to have a different view on the role of the supervisor than Heinrich. In Bird’s opinion the supervisor does exactly what the big bosses want, so according to Bird the key persons are not the direct managers, but the highest up in the organization. Weaver, in turn, does focus on the supervisors just like Heinrich.
The theme about hidden costs is another that gets some discussion and revision. The 4 : 1 ratio is dismissed with “that was in 1926” and some newer studies are mentioned, especially the Bird iceberg (p.89) and wisely the authors remark: “to actually quantify hidden cost is an almost impossible task and probably not worth the effort. If management believes in the concept it is often unnecessary to quantify”.
The chapter ends with the safety-efficiency axion that has a lot going for it (unsafety leads to loss, i.e. it is not efficient), but with ETTO (something nobody had written about in 1980) in the back of your mind also against it.
Having discussed the basics of the original Heinrich books, we enter Part II of the book on ‘Accident-Prevention Method’, or shouldn’t it rather be ‘methods’ instead? Chapter 3 is basically about two flowcharts (well, kind of) of the accident handling process from fact-finding and analysis to measures and monitoring of those. The various steps from these flowcharts are discussed in further detail in chapters 4 to 9.
Chapter 4 deals with collecting and analyzing data. Slightly unlucky is the fact that they talk about “a subcause”; while they earlier in the book discussed multiple causes, it’s a bit unclear if they propagate linear single causal connections after all. What I like a lot is that they do (yet without saying it explicitly) discuss the relative character of the terms “cause” and “effect”. Really good, since people tend to forget that every effect (or consequence, if you want) can be the cause of something else. And what is absolutely a good thing of this 5th edition in comparison with its predecessors, is that it breaks with Heinrich’s focus on direct causes by (justly) stating that these are merely symptoms of underlying weaknesses.
Pages 109-111 present Weaver’s TOR tracing system for root causes. A high ‘investigation by checklist’ level here, so not my thing. And then the ‘whether’ question… I mentioned already the danger for counterfactual reasoning. Another problem I have with this is that the authors (and Heinrich before them, by the way) entirely forget to discuss risk assessment as the (or at least a) basis for safety management. Also do the authors tend towards a compliance driven ‘whether’ later in the chapter. Not their finest moments here.
Chapter 5 discusses System Safety and finally we get some discussion of hazard identification, even though I do not fully agree on the author’s definition of hazard. But that’s sifting through details. What I do like a lot is their thoughts on the occurrence of accidents through either 1) energy transformation (though unsafe act or condition) or 2) energy deficiency (which causes a safety critical function to fail, e.g. a plane’s motor). Handy and often applicable.
Accident Analysis is the subject of the next chapter. Take care that the authors apply a certain meaning to the words ‘investigation’ and ‘analysis’. Many of us may think about ‘investigation’ in terms of fact finding and checking hypothesis about the causes while ‘analysis’ is about the identification of the various causes. When the authors talk about accident analysis they mean the analysis of trends. It is very interesting to see how important the authors think that trend analysis is, but then, they saw the iceberg/pyramid as a major opportunity, so it shouldn’t be surprising to read that they find this a “necessary prerequisite to the selection of an effective remedy” (p.134 and also bottom p.135). I fully agree.
Quite funny from today’s point of view: a lot of fuzz about how easy working with a computer can be. Duh!
Chapter 7 deals with the selection of a remedy. For starters they discuss the ‘old Heinrich axiom’ and conclude with that the “engineer the hazard out” as first choice is just a good and sound advice. After this follows a whole bunch useful stuff about cost/benefit analysis, Kepner Tregoe’s 7 steps and a bit of Fine and Kinney. The following chapter, Application of Remedy, is for the greater part a direct copy of older versions of the book and then ends up in a lot of details, e.g. about slips and falls.
Chapter 9 deals with Monitoring, and it’s good that the book has a lot of attention for this important issue. As the authors say, reasons for monitoring could or should be: 1) gauging performance, ‘how are we doing’, 2) providing us with red flags when thing go wrong, and 3) a measure of performance for the responsible individuals. A major part of the chapter (around p.210) is quite useful as input for an eventual self-evaluation questionnaire. As for a methodology of monitoring an important tip is provided: “the past performance of any group is the best standard to use as a guide for present performance” (p.225) because people in the group understand it and will accept it, and obviously it will measure if there is improvement. On the same page the authors even discuss ‘leading’ indicators - excellent! A shame that they also dwell on LTIF for a while… And one good point that underlines Bird’s opinion on managers: “managers are first and foremost motivated by their bosses’ measures of their performance” (p.226).
Chapter 10, Creating and Maintaining Interest, is for the first part again a direct copy of Heinrich’s original text. After this we get a quick run through of a lot of behavioral theory on motivation (Maslow, Argyris, Herzberg), learning (Skinner), interpersonal skills, communication and management theory. As a whole this is a great improvement on Heinrich’s original pseudo-psychology and a fine summary of some important psychological theory for the safety professional. Basically recommended reading.
One more worthwhile quote: “The key to employee safety performance is a management that cares and does something to demonstrate that caring. The key to supervisory performance is doing something to make it matter to the supervisor whether or not he performs in safety”.
Chapter 11 picks up the Motivation Model from chapter 2 once more and in more detail. First we get another short discussion of accident proneness (which was already dismissed in chapter 2 in a most effective way by applying statistics and normal distribution - on some other grounds too. Very strong piece of applied science if you ask me… on p.42): “accident proneness is real, but extremely rare”, so with regard to accident prone susceptible people: “don’t waste time on that either” (p.261/262). And on we go to more useful matters like ability determinants, proper placement (where I would have said something about guidance and tutoring, but maybe that’s included in training and supervision?), training, climate (“the way we see the company safety program strongly influences the behaviour and ability to learn”, p.262), if it’s a lively company (lively being a good characteristic of the company’s culture and learning ability) and the friendliness of safety people (an interesting point that may serve as a mirror for some safety professionals).
A large part of the chapter is actually used on discussing the safety culture/climate in a company. Page 264 addresses the discrepancy between climate perceived by the workers and the climate that is intended and poses the question if enough effort has been spent guiding the philosophy down the line. If the superior does not reflect the organization’s philosophy there will be a perception discrepancy! Again ahead of their time (Schein’s work came after this book I believe - have to check) the authors concluded that safety climate (culture) is a product of both the corporate climate and a functioning safety program (p.268).
The text goes on listing Scanlon’s basic climate requirements: 1) Overall goals and objectives; 2) Objectives communicated; 3) Goals distributed over departments; 4) See the big picture instead of sub-optimalization; 5) Meaningful participation of the individual and 6) Freedom to work, relatively autonomous. A good list to keep in the back of your mind. Page 265 has an interesting discussion of communication and the danger of ending up in bureaucracy. One key element in a good safety climate is a turn from authority orientation (do as you’re told) to goal orientation (“if a worker explains the job to do/done and what it will achieve for the company”). It’s also argued that stability is essential for a good climate, which is typical because stability and the mentioned expansion aren’t necessarily simultaneous things, but expansion and job security maybe a bit more…
Likert promotes participative management because this leads to higher levels of achievement (p.266), something that is worked out further in the text, e.g. by supportive relationships, group decision making and group methods of supervision. Participation is essential according to the authors: “participation and its resultant commitment become a substitute for authority”.
The chapter concludes with a discussion of what motivates and what not. Quite a surprising list of satisfiers (things that lay in the job itself) and dissatisfiers (stuff peripheral to the job, at best functioning as “short time teasers”, like payment - even though people do adopt behaviour and perform actions for positive reward).
Chapter 12 deals with Safety Training and once more copies a big deal of original text from Heinrich. Most striking is the conclusion that the method of training isn’t as important as other variables including motivation through working towards a goal, reinforcement, practice, feedback, meaningfulness and the climate/culture. And: “if the supervisors are thoroughly sold on safety, they in turn will sell the employees whose work they direct” (p.277). To support this then chapter 13 has a ‘formula for supervision’. The text discusses the paradox in supervisors being key personnel for quality, safety, maintenance and direct control of employees, but that this is hardly ever taught to them. The text does not give a 100% solution, but if I can summarize it comes very close to the famous plan-do-check-act principle. And a very wise observation: supervisors don’t have the same motivators like ordinary employees, exactly because of their position.
The last few chapters are of lesser interest, dealing for a major part with insurance issues and legislation that is utter irrelevant for professionals outside the USA and probably superseded by now for those in the States. Most interesting is Chapter 16 on Risk Management which also makes clear that risk management and safety management don’t always have the same goals. Sharpest division is when they discuss the function of the safety manager (who aims to control/prevent losses) and a risk manager (who also funds for losses that occur, and will even try to transfer the risk to someone else, the latter being hardly acceptable in safety).
This book also concludes with a number of appendices of which again the historical one are of greatest interest.
Concluding, I would say that this is a very useful update of Heinrich’s original work with a good critical approach and a lot of new knowledge added. Much of the book (especially the central parts) stands to this day and it would have nice to have seen a sixth edition with updated knowledge from the past 30 years of safety science. To my knowledge no such book exists, however. What does exist is a very critical book on Heinrich which we will take on next.
Details about the book:
Industrial Accident Prevention, H.W. Heinrich, Dan Petersen, Nestor Roos, 1980 (5th edition), McGraw-Hill Book Company (ISBN 0-07-028061-4)