Safety Science 63 (2014) 1–7

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Safety Science

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Development of safe design thinking among engineering students

0925-7535/$ - see front matter � 2013 Elsevier Ltd. All rights reserved.http://dx.doi.org/10.1016/j.ssci.2013.10.018

⇑ Corresponding author. Tel.: +1 252 328 9674; fax: +1 252 328 1618.E-mail address: behmm@ecu.edu (M. Behm).

Michael Behm a,⇑, John Culvenor b, Gene Dixon c

a East Carolina University, 231 Slay Hall, Greenville, NC 27858, USAb 40 Wilfred Road, East Ivanhoe, Victoria 3079, Australiac East Carolina University, 205 Slay Hall, Greenville, NC 27858, USA

a r t i c l e i n f o a b s t r a c t

Article history:Received 22 May 2013Received in revised form 1 September 2013Accepted 27 October 2013

Keywords:Safe designEngineeringEducation

The National Institute for Occupational Safety and Health (NIOSH) Prevention through Design (PtD) ini-tiative recognizes engineering education as a primary source to infuse safe design knowledge with thepurpose of affecting change in the United States. In line with NIOSH objectives, we: (1) develop andimplement a PtD education intervention with engineering students, and (2) measure the change inknowledge and comprehension of occupational health and safety principles from an engineering designperspective from students’ first-year to fourth-year. The intervention is an addition to engineering curric-ula and was applied to a cohort of undergraduate engineering students evaluated as a one group pretestposttest design. Over the time from first-year to fourth-year, the engineering students’ thinking devel-oped and changed regarding their design responsibility, what causes accidents, how they can reduce risk,and in applying the concepts in case studies. There was a shift in thinking from safe people to safe placeand recognition that the hierarchy of controls can be utilized by engineers. The results supplement NIOSHgoals and contribute to the body of knowledge in safe design education.

� 2013 Elsevier Ltd. All rights reserved.

1. Background

In the United States, the National Institute for OccupationalSafety and Health (NIOSH) Prevention through Design (PtD) initia-tive recognizes that ‘‘one of the best ways to prevent and controloccupational injuries, illnesses, and fatalities is to ‘design out’ orminimize hazards and risks early in the design process’’ (NIOSH,2011). The approach to implement the initiative is framed withinfour functional areas: research, practice, education, and policy(Schulte et al., 2008). Within secondary and graduate education,the disciplines of engineering, architecture, and business most fre-quently are identified as prime opportunities for PtD education(Mann, 2008). Intervention development has already begun;NIOSH has developed four PtD lecture modules: reinforced con-crete design, mechanical and electrical systems design, structuralsteel design, and architectural design and construction (Heidel,2011).

Cowley and Murray (1992) contended that as fewer engineersare entering the occupational health and safety (OHS) professionand the misconception that engineering controls are difficult pre-vails, the full potential of the OHS discipline in improving the stan-dard of workplace safety and health cannot be realized. OHSproblem solving and improvement follows a hierarchy of controls.The American National Standards Institute (ANSI) states that the

hierarchy ‘‘provides a systematic way to determine the most effec-tive method to reduce risk associated with a hazard’’ (ANSI, 2012,p. 15). The hierarchy of controls in ANSI Z10 (2012) has six solutioncategories. In order of preferred problem solving efficacy, they areElimination; Substitution of less hazardous materials, processes,operations, or equipment; Engineering Controls; Warnings;Administrative Controls; and PPE. For engineers and design profes-sionals the hierarchy has been described as the acronym ERIC; inorder that is eliminate, reduce, inform, and control (CITB, 2007).Eliminating and reducing hazards and risks means active designchanges, whereas informing means passing information onto thecontractor/operations/maintenance teams about the residual riskwhere a design change was not reasonably practicable in the de-signer’s professional judgement. Control of the residual risk is inthe hands of other on-site duty holders (CITB, 2007).

An often referenced diagram in the safe design literature is fromSzymberski (1997); he proposed that the ability to influence sitesafety is inversely proportional to a project’s schedule. We havemodified his graph by replacing the ‘‘ability to influence safety’’with ‘‘ability to utilize higher order controls’’. See Fig. 1. In otherwords, the ability to effectively utilize the hierarchy of controls isgreater the earlier in the project you attempt to solve occupationalsafety and health issues. Once the hazard is on the site or fixedwithin the work system, many times the only feasible solution isto implement lower order controls, such as warning, procedures,training, and PPE. The hazards are already there; we cannot elimi-nate them or reduce them due to their purpose, cost of retrofit, or

Fig. 1. Ability to utilize higher order controls (elimination, substitution, engineer-ing) over time. Adapted from Szymberski (1997).

2 M. Behm et al. / Safety Science 63 (2014) 1–7

timing. Workers and safety professionals have little opportunity toutilize the higher order controls and be innovative. This is not tosay workers and safety professionals are not innovative, and in factquite the contrary, they are very creative and resilient to reducerisk within their sphere of influence. However, their sphere ofinfluence is limited compared to other upstream entities, such asengineers and designers, who have a greater opportunity to elimi-nate and reduce hazards and risks.

Gambatese and Hinze (1999) recommend that one of the meansby which engineers can become more responsive to the safetyneeds of workers is through education. Engineers must be madeaware of the various means by which their design decisions impactthe jobsite safety conditions for construction workers. The way adesign professional thinks about safety will influence their deci-sions and philosophies about designing for safety. Culvenor(1996) describes this as a safe place or a safe people philosophy.A safe place philosophy focuses on the source of hazards and canbe more easily implemented in the design and upstream phases.On the other hand, if the engineer believes in the safe people phi-losophy, then why bother evaluating it to eliminate or reducewhen controls should be implemented at the site.

Safety and engineering are often tied together in higher educa-tion. For example, in Europe, engineering schools were found to bethe most common place where OHS graduate courses and degreeswere offered (Arezes and Swuste, 2011). This is not the case in theUS. Although safety is considered as an important area of engineer-ing instruction, particularly for practicing engineers, it is often notaddressed adequately in a curriculum (Heidel, 2011; Noakes et al.,2011). There was a clear consensus in the education group of the2007 NIOSH PtD workshop that PtD will be best introduced in edu-cational curricula through modules, rather than in completecourses (Mann, 2008). The main reason given is that the US engi-neering curriculum is already full with courses and there is noadditional room for another required course. Authors in the UnitedKingdom (HSE, 2009), and Australia (Culvenor and Else, 1997)found this to be the case as well. Davidson et al. (2010) observedthat few engineering schools have made major updates to theircourses and curricula over the past few decades.

Other engineering education authors have described efforts insystem or process safety (Noakes et al., 2011; Louvar, 2009; Dahoeand Molkov, 2008). Our study is a look at occupational or personalworker safety. Reason (1997) distinguished between these types ofsafety; however, he notes the similarities in the preventive ap-proach to both. The discipline of chemical engineering focuses onsafety and inherent design. In chemical engineering, Brennan(2006) highlighted the need for operations knowledge to apply safeand inherent design for normal operations and how operators re-spond to unforeseen events. Noakes et al. (2011) described devel-oping an animated software teaching module to teach a processsafety technique to chemical engineering students. Saleh and

Pendley (2012) highlight the importance of safety literacy andthe contributions that engineering students can make in thelong-term towards accident prevention. They describe a modelfor the structure and content of an introductory course on ‘‘sys-tem’’ accident causation noting the differences between systemand occupational accidents (Saleh and Pendley, 2012). While previ-ous archival literature describes the educational interventions orthe recommended methods, there is no clear assessment. Educa-tional interventions and their effectiveness in changing engineer-ing student knowledge and perceptions with regards to OHS arelacking in the peer-reviewed archival literature. The focus on occu-pational health and safety and its evaluation are our points ofdeparture for the research; they are also our contributions to thebody of knowledge.

Specifically, NIOSH has a PtD Education Strategic Goal that,‘‘Designers, engineers, machinery and equipment manufacturers,health and safety (H&S) professionals, business leaders, and work-ers understand PtD methods and apply this knowledge and skills tothe design and re-design of new and existing facilities, processes,equipment, tools, and organization of work.’’ (NIOSH, 2011, p.24). Within that strategic goal NIOSH (2011, p. 25) also has a spe-cific activity/output goal to ‘‘enlist the support of Deans of Engi-neering Schools to include basic PtD principles and occupationalsafety and health principles in required engineering courses’’.

2. Methodology

2.1. Research objective

The objectives of the research were to: (1) develop and imple-ment a PtD education intervention with engineering students,and (2) measure the change in knowledge and comprehension ofoccupational health and safety principles from an engineeringdesign perspective from students’ first-year to fourth-year.

2.2. Instrument

We utilized a survey that asked the students about their per-ceived design responsibility, what causes accidents, what can bedone to prevent or minimize accidents, and asked them to rankproposed solutions in four case studies. The survey utilized ques-tions with a 5-point Likert scale (Strongly Disagree to StronglyAgree) and ranked answers; it has been utilized in previousresearch (Behm and Culvenor, 2011). The tables in the Results sec-tion reveal the questions. The University Institutional ReviewBoard approved the survey for participants 18 years and older(#10-0047). Alternative hypotheses, along with the measurementand statistical analysis in parenthesis, are listed below. Data aretreated as paired data for statistical analyses.

Ha1. There is a change in the perceived design responsibilityamong engineering students from their first-year to fourth-year (5-point Likert scale, Strongly Disagree [1] to Strongly Agree [5]; t-test).

Ha2. There is a change in the perception of what causes accidentsat work among engineering students from their first-year tofourth-year (5-point Likert scale, Strongly Disagree [1] to StronglyAgree [5]; t-test).

Ha3. There is a change in the perception that accidents are pre-ventable among engineering students from their first-year tofourth-year (1-Less than half; 2-Hardly any; 3-Half; 4-More thanhalf; 5-Nearly all; t-test).

M. Behm et al. / Safety Science 63 (2014) 1–7 3

Ha4. There is a change in the perception of how accidents at workcan be prevented among engineering students from their first-yearto fourth-year (ranking of 8 answers; Wilcoxon signed rank).

Ha5. There is a change in the practical implementation of the hier-archy of controls in recommending solutions to worker safety casestudies among engineering students from their first-year to fourth-year (correlation of the 6 ranked risk reduction solutions to expertpanel prioritized based on hierarchy of controls).

In the four cases studies (Ha5), students were asked to prioritizefrom a list of six solutions from most effective to least effect interm of their risk control potential. The students’ ranked solutionswere correlated with a standard rank prioritized based on the hier-archy of controls. As a means of validation of these standard ranks,Culvenor (1997) used an expert panel of safety researchers to pri-oritize the solutions. These case studies were utilized in previousresearch (Culvenor, 2003, 1997; Culvenor and Else, 1997). Belowis an example of one of the cases; Table 1 shows the standard rank-ing in accordance with the hierarchy of controls, and the rationale.For a complete description of the case studies see (Culvenor, 2003,1997).

TaSta

Case study example. Karen worked in a food processing factoryas a production engineer. A forklift collided with Karen causingmultiple fractures and severe bruising. Bill, a storeman, uses aforklift to shift drums of liquid. He moves the drums from thereceiving storage area to the production area. The accidenthappened at 7 pm on a winter night. The lighting in theproduction area was good but the lighting in the storage andforklift ‘roadway’ area was poor. Karen was walking fromthe well-lit Tea Room across the ‘roadway’ when struck bythe forklift. The load obstructed Bill’s view. The noise of theproduction line obscured the forklift motor noise. People can walkaround the factory on an elevated walkway, but this is not alwaysconvenient and often not used despite a company rule.

2.3. Sample population

The university’s engineering program is a general engineeringprogram with concentrations in biomedical, bioprocess, industrialand systems, electrical, and mechanical engineering and is accred-ited by ABET (formerly the Accreditation Board for Engineering andTechnology). Our design is a non-experimental pre-post one groupdesign. The limitations will be discussed in the section 4.1.

ble 1ndard ranking for the food processing case study based on hierarchy on controls and e

Standard rank

1. Pipe the liquid from the receiving storage area to the production area

2. Build a conveyor to carry the drums from the receiving storage area to the productio

3. Provide forklifts with dual controls such that they can be driven in reverse4. Improve the lighting in the ‘roadway’ section of the factory

5. Install a beeper on the forklift

6. Create a strict rule that in the interests of safety the existing walkways must be u

We surveyed a cohort of engineering students in their first yearand then again prior to graduation in their fourth year. In the first-year, we surveyed 70 engineering students out of a possible 98(71%). By year 4 in the second semester, the engineering studentpopulation dropped to 39 students from the original cohort, a60% (59/98) attrition rate. Some students got behind on theircoursework and are still in the Engineering program while otherschanged majors, transferred to another university, or droppedout of school. We do not have exact numbers on the reasons whystudents left Engineering. The National Academy of Engineering(2005) reported that ‘‘only 40 to 60 percent of entering engineeringstudents persist to an engineering degree’’. Attrition of studentsfrom first to fourth-year is a potential limitation to the analyses,but is in line with national statistics. In Year 4, 90% of the studentsresponded (35 of 39). Seven of the respondents in Year 1 were fe-male (10%). Five of the respondents in Year 4 were female (14%).

2.4. Engineering education – traditional

The university’s engineering curriculum emphasizes safetythrough the use of case studies embedded in courses throughoutthe curriculum. The case studies commonly used include the HyattRegency Walkways, Chernobyl, Challenger, Hindenburg, TacomaNarrows Bridge, Titanic, and the Gulf Oil Spill. Each of these pres-ent the ethics of practicing engineering by pointing out the role ofsafe design, safe construction methods, and safe usage. The seniorcapstone course includes a module where students examine theintegrated role of human factors/ergonomics. One of the featuresof this discussion is a description of a nuclear production reactorindicators and human error potential. Safety factors in design asso-ciated with piping, structural components and other loaded andload bearing applications are also discussed. This content is typicalof US undergraduate engineering curriculum and is focused on eth-ics (Colby and Sullivan, 2008). However, the focus is at the struc-tural, process, and public safety level, not at the worker level tounderstand their needs to safely construct, operate, maintain,and decommission the product, process, product, or technology.This is the crux of the additional intervention.

2.5. Engineering education – PtD intervention

Consistent with what Mann (2008) found at the NIOSH PtD2007 workshop, there was no room in the curricula for an entirecourse on PtD focused on occupational safety and health. Theauthors worked with Engineering faculty to integrate safe designconcepts where the group felt they would be most appropriateand where there was room for such additional modules. A 70-min lecture, with time for discussion, was delivered to theengineering students in their third year as part of an Engineering

xpert panel (Culvenor, 2003, 1997).

Rationale

Eliminates the forkliftEliminates the energy

n area Eliminates the forkliftEliminates the energyCreates further energy source in comparison to the piping solutionImproves control over the energy as driver has unobstructed viewImproves control over the energy as driver has better visionRecipient should be better able to maintain separation with bettervisionDoes nothing about energy or controlRecipient may be better able to maintain separation due to the warning

sed Separates recipient and energyRule already exists and is ineffective

4 M. Behm et al. / Safety Science 63 (2014) 1–7

Project Management class. The lecture and discussion wasdeveloped and delivered by the first author, an occupational safetyacademic and a member of the NIOSH PtD Council. The archivedaudio and video link to the lecture can be found at, http://gc.ecu.edu/Mediasite/Play/b3ca8454b0b84d4b936e0b3e9a5484151d. Wehope that including the archived link would add to the body ofknowledge and allow replication, improvement, and tailoring thecontent to meet others’ needs. The lecture included the followingtopics:

� Fundamental concepts in the discipline of occupational healthand safety (in contrast to structural safety, life safety (egress),and public safety).� The causes and factors of occupational accidents.� The concept of safety through design with a focus on the worker

and worker safety across the life cycle (construction, operation,maintenance, and commissioning).� Hierarchy of controls as a method of problem solving.� Safe design as a source for engineering innovation.� Numerous examples were utilized in each topic area described

above and the presentation was picture intensive.

In the cohort’s fourth year, as part of the senior design course,the Engineering students were given two fatality case studies ashomework. They were given the summaries and investigation de-tails of 2 NIOSH Fatality Assessment and Control Evaluation (FACE)where there safe design and engineering implications. All recom-mendations were removed. The cases dealt with a solar panel in-staller falling through a skylight (http://www.cdc.gov/niosh/face/stateface/CA/09CA003.html) and a drilling operator who struckan overhead power line (http://www.cdc.gov/niosh/face/state-face/ak/99ak019.html). Students were asked to think like an engi-neer and generate a list of solutions to reduce risk in the twofatality cases. These were different case studies than used in thesurvey. Individual feedback was provided to each student; it cen-tered on whether solutions provided were largely based on designchanges, process alterations, and better planning and coordinationof the work, or if solutions provided largely relied on lower ordercontrols such as behavior changes, work procedures, training,awareness, warnings, and personal protective equipment. An in-class discussion on their answers and ideas to reduce risk in thecase studies was coordinated. The discussions focused on whatan engineer could do in the design of the project or product inquestion. Additional examples of safe design engineering ideaswere discussed in this lecture/discussion. Prior to graduation, thesame survey was distributed and compared to their first-year re-sponses to measure change in knowledge and awareness of OHSprinciples and how engineers can affect safety through theirdesign.

3. Results and discussion

Ha1. There is a change in the perceived design responsibilityamong engineering students from their first-year to fourth-year(5-point Likert scale, Strongly Disagree [1] to Strongly Agree [5];t-test).

Results between the Engineering students’ first and fourth-yearwere largely the same (see Table 2). The one exception directly re-lated to PtD was to the statement of ‘Access for workers who repairor maintain the item’. Mean scores increased from 4.10 to 4.49(p < 0.01). This is a positive outcome that the group would nowconsider this aspect of design more important than when theywere in their first-year. Several examples in the junior year lecture

focused on design of safe access, designing to eliminate fall haz-ards, and designing fall protection systems during maintenanceof roofs and atria, and changing light bulbs.

Ha2. There is a change in the perception of what causes accidentsat work among engineering students from their first-year tofourth-year (5-point Likert scale, Strongly Disagree [1] to StronglyAgree [5]; t-test).

Comparisons from first to fourth-year are summarized inTable 3. The mean score of poor layout of the workplace increasedfrom 3.50 to 3.97 (p = 0.01). The students’ perception that careless-ness of the injured worker causes accidents was lowered from year1 (4.27) to year 4 (3.91). Both changes indicate a shift in thinkingfrom safe people to safe place philosophy. Although not statisti-cally significant, an examination of the mean score changes ofthe other questions indicate a potential shift to safe place philoso-phy. The exception was student perceptions regarding unsafeconditions.

Ha3. There is a change in the perception that accidents arepreventable among engineering students from their first-year tofourth-year (1-Less than half; 2-Hardly any; 3-Half; 4-More thanhalf; 5-Nearly all; t-test).

Fourth-year students felt that accident s are still preventable(�X ¼ 4:60). The result is higher than their first-year response(�X ¼ 4:33), but is not statistically significant (p = 0.08).

Ha4. There is a change in the perception of how accidents at workcan be prevented among engineering students from their first-yearto fourth-year (ranking of 8 answers; Wilcoxon signed rank)

Table 4 provides results of the Wilcoxon signed rank test whichcompared Year 1 to Year 4 ranking of ideas on how accidents atwork can be prevented. Z-scores based on negative ranks (notedby a superscripted 1 in Table 4) indicate that the priority of thisidea is less in Year 4 compared to Year 1. Z-scores based on positiveranks (noted by a superscripted 2 in Table 4) indicate that the pri-ority of this idea is greater in Year 4 compared to Year 1. For exam-ple, training workers in how to behave safely is less of a priority forthe engineering students after the intervention. Seven of the eightresults support the notion that a safe place philosophy is emerging.Buying safe equipment in the first place is a higher priority in Year4, but is it not statistically significant. These results are congruentwith the students’ changed perceptions of what causes accidents.

Assessment of students’ written responses to the fatality casestudies and in the follow-up class discussions revealed that theirideas to prevent the fatality was a mix of higher and lower ordercontrols. For example, in the solar panel installer fall case, studentsrecommended passive controls (guardrails, stronger skylights,etc.), but also recommended active controls (horizontal lifeline sys-tem) and discussed the importance requiring workers to wear fallprotection equipment. They recognized multiple solutions and theinterconnectedness of safe place and safe people.

Ha5. There is a change in the practical implementation of thehierarchy of controls in recommending solutions to worker safetycase studies among engineering students from their first-year tofourth-year (correlation of the 6 ranked risk reduction solutions toexpert panel prioritized based on hierarchy of controls).

The purpose of the accident case studies was to examine howthe engineering students would actually apply the hierarchy ofcontrols in an example. A 1.0 correlation would indicate that theranking of the listed ideas was identical to the hierarchy of controlsand the expert panel or a safe place philosophy, as described in the

Table 2Perceived design responsibility.

Thinking generally, when designing an ‘‘item’’ (structure, machine, material, process, tool, work system, etc.), it is a designer’sresponsibility to design/allow for ...

Year N Mean SD p-Value

The item’s purpose - e.g. capacity, power, size, output 1 70 4.37 .641 <0.014 35 4.71 .519

How safe the item will be to manufacture/build 1 69 4.29 .644 0.854 35 4.31 .631

Eventual users/workers who don’t have their mind on the job 1 70 3.07 1.068 0.134 35 3.40 .946

How the item will be refurbished 1 70 3.66 .778 0.494 35 3.77 .843

Keeping the design to budget 1 70 4.14 .785 0.124 35 4.40 .775

Uses to which the item could be put other than the original purpose 1 70 3.34 .991 0.794 35 3.29 1.152

Access for workers who repair or maintain the item 1 70 4.10 .640 <0.014 35 4.49 .612

Workers/users who take short cuts when using the item 1 70 2.70 1.012 0.664 35 2.80 1.232

Information that will be needed to use the item safely 1 68 4.40 .650 0.294 35 4.54 .657

Making the item reliable – e.g. avoiding structural failure, overbalancing, breakdowns, overheating, etc.) 1 70 4.56 .673 0.214 35 4.71 .458

What will happen with the item is no longer needed 1 70 3.26 .988 0.074 35 3.66 1.056

Table 3What causes accidents at work?

What causes accidents at work? Year N Mean SD p-Value

Poor equipment 1 68 3.46 1.071 0.114 35 3.74 .701

Lack of hazard control planning bymanagement

1 69 3.49 1.038 0.30

4 35 3.69 .796Poor layout of the workplace 1 70 3.50 .881 0.01

4 35 3.97 .747Unsafe working conditions 1 70 3.63 1.052 0.89

4 35 3.60 .946Carelessness of the injured worker 1 70 4.27 .850 0.04

4 35 3.91 .781Accident-prone workers 1 70 3.31 1.043 0.14

4 35 3.03 .857Inexperience of the injured person 1 69 4.04 .716 0.53

4 35 3.94 .802Lack of training in how to behave safely 1 70 4.01 .985 0.11

4 35 3.69 .963

M. Behm et al. / Safety Science 63 (2014) 1–7 5

Methodology section. A -1.0 correlation would indicate a safe per-son philosophy meaning that the engineering student would be-lieve that ideas like procedures, work rules, and training arepreferred to improved equipment, conditions, and hazard elimina-tion. Table 5 summarizes the mean correlation coefficients (r) fromthe students from year 1 to year 4. Fig. 2 visually depicts the data.In Year 1 all correlations are negative, ranging from -0.45 to -0.64;this indicates a fairly strong belief of the first-year engineering stu-dents that people are the problem and they as engineers cannot beof much assistance in OHS. Year 4 shows a statistically significantincrease in the mean r in all four case studies. The engineering stu-dents learned something and as a group they have changed theirthinking compared to Year 1. However, 3 of the 4 are still negativeand the fourth is essentially not correlated. In practice the fourthyear students still largely believe that people are the problem. Thisresult does not support the effectiveness of the educational inter-vention. Additional case studies may be needed and integrationof safe design thinking could be better reinforced in the capstonedesign project. On the other hand, perhaps it is unrealistic to thinkthat the graduating engineer will be able to conceptualize the topicvery well without real world experience.

A larger standard deviation (SD) in Year 4 data is of some inter-est. The final column in Table 5 indicates the percentage of respon-dents with an individual positive correlation coefficient. The datasupports the intervention did impact some students and changedtheir application – in all four case studies the percent of studentswith a positive r increased from Year 1 to Year 4. The averageacross the four case studies in Year 1 was 12% compared to 35%in Year 4.

4. Discussion

A positive change was measured on students’ knowledge andcomprehension of design responsibility, what causes accidents,how they can reduce risk, and in applying concepts in case studies.There was a shift in thinking from safe people to safe place and rec-ognition that the hierarchy of controls can be utilized by engineers.Was the change in perceptions a result of the intervention or thedevelopment of their engineering thinking maturity over thecourse of their education or some combination? Our study designmakes it unrealistic to solely measure the intervention’s effects;rather, our measurements represent the development of the engi-neering students’ safe design thinking over time. The results areconsistent with the aims of the program.

For example, the students now think that part of engineeringdesign should include considering access for workers who repairor maintain the item. Hale et al. (2007) recognized the importanceof considering safe design for maintainability contenting thatdesigners ‘‘may also think too little about the maintainability oftheir equipment’’, thus requiring maintenance staff to take exces-sive risks to get their work done effectively and efficiently. The casestudy results exhibit a difference in applying in the principles;however the change is not sufficient. The correlations are negativeindicating a safe people philosophy or at best no correlation. Appli-cation of a concept is a higher level of learning compared to knowl-edge and comprehension. Students recognized that design andbehavior often affect each other mutually.

The intervention was constrained by what could fit into an al-ready packed engineering curriculum. An expanded OHS interven-tion should include PtD principles in most other classes rather thanlimiting it to two classes. Integrating PtD examples into textbooksand cases studies would place OHS in the decision logic of students

Table 4How accidents at work can be prevented, change from Year 1 to Year 4 (Wilcoxon Signed Rank).

How accidents at work can be prevented (ranked) Z P-Value Interpretation

Training workers in how to behave safely �3.436a <0.01 Lower priority in Year 4Indicative of safe place philosophy

Hazard control planning by management �4.096b <0.01 Higher priority in Year 4Indicative of safe place philosophy

Workers taking more care �5.301a <0.01 Lower priority in Year 4Indicative of safe place philosophy

Fixing unsafe working conditions �1.956b 0.05 Higher priority in Year 4Indicative of safe place philosophy

Making sure accident-prone people get special training �3.360a <0.01 Lower priority in Year 4Indicative of safe place philosophy

Buying safe equipment in the first place �1.567b 0.12 Not statistically significantShowing inexperienced workers about the worst hazards �3.242a <0.01 Lower priority in Year 4

Indicative of safe place philosophyAsking workers about their ideas to control hazards �3.952b <0.01 Higher priority in Year 4

Indicative of safe place philosophy

a Based on negative ranks.b Based on positive ranks.

Fig. 2. Mean correlation coefficients across 4 case studies.

6 M. Behm et al. / Safety Science 63 (2014) 1–7

with each class they take and better reinforce the notion that OHSis not an add-on idea. The foundational concepts of PtD should beintroduced to first-year students so that they can then build onthese in other classes. In our intervention, we introduced theseconcepts via a lecture in the third-year. This is likely too late.Our final opportunity with the students was in their senior year, fi-nal semester capstone design course. This course provides studentswith a real world design opportunity. Future senior design coursesshould include PtD as a grading criterion in the capstone designproject.

Colby and Sullivan (2008) analyzed engineering ethics educa-tion and found that all professional engineering codes of ethicshave a ‘‘central emphases within the broader category of the engi-neer’s responsibility to contribute to human welfare are the over-riding values of public safety and protection of the environment.’’However, the distinction between ‘public’ safety and worker oroccupational safety is important. In the US it is clear that workersare not part of the public in the scope of this definition (Mann,2008).

4.1. Limitations

The results are from a single university and do not have thebenefit of a control group. Shannon et al. (1999) identified fourmain threats to internal validity in before-and-after interventionstudies with a lack of a comparison group as history, maturation,testing, and instrumentation. There were 39 months between thepretest and the posttest. During the students’ educational experi-ence there was no noticeable evidence of historical events thatmay have influenced perceptions. The students matured in theirengineering thinking over the 39 months. The length of the studyassisted in controlling the testing effect, which Shannon et al.(1999) describes as the posttest shows a different result simply be-cause the pre-intervention measurement created an effect. Fur-thermore, there was no feedback provided after the pretest.

Table 5Case study correlations.

Case study Year N Mean r SD P-Value % + r (%)

Case Study 1 1 70 �0.54 0.33 <0.01 5.74 35 �0.21 0.53 31.4

Case Study 2 1 70 �0.64 0.29 <0.01 5.74 35 �0.24 0.48 28.6

Case Study 3 1 70 �0.45 0.43 0.02 16.94 35 �0.22 0.46 28.6

Case Study 4 1 70 �0.47 0.44 <0.01 19.74 35 0.02 0.54 51.4

Shannon et al. (1999) describe the instrumentation effect as occur-ring when there is a change in the means of obtaining outcomemeasurements between pre- and post-testing. Our test remainedthe same.

5. Conclusions

The study presented a PtD educational intervention aimed atraising knowledge and comprehension of OHS principles from anengineering design perspective embedded within a broader ter-tiary program. The evaluation showed a positive effect on mea-sures of perception regarding safe design. Engineering students’perceptions of accident causality and prevention changed to favorsafe design thinking in Year 4 after the educational intervention.While the effect of neither the broader education nor time can beseparated from the PtD intervention, the results are consistentwith the aims of the program. The lack of a control group coupledwith the attrition rate is a major limitation in determining theeffectiveness of the educational intervention. It can be contendedthat the students who remained in the engineering curriculum ma-tured in their engineering thinking more readily than the lessinterested students and safe design thinking is simply part of thatmaturity.

Authors referenced in the paper and organizations, such asNIOSH, contend that engineering students need safety education.The development and implementation of the PtD educational pro-gram for engineering students supplement previously mentioned

M. Behm et al. / Safety Science 63 (2014) 1–7 7

NIOSH goals. The measurements establish baseline views and howthey coincide or clash with the kind of thinking that NIOSH is try-ing to address in engineering student development. We offer onemethod of integration and make it as transparent as possible forreaders to make a decision, but to claim it was the intervention so-lely would be careless. The changes we observed are due to theintervention combined the student’s development and maturationto become entry-level engineers. Our contribution to the body ofknowledge is evaluating engineering students change in thinkingand maturity over time. It is hoped that future researchers andeducators can use our study as a baseline to begin establishingand strengthening a body of science on the thinking of the engi-neering and design community.

Engineering has a very crowded curriculum. Our interventionfollowed the advice of Mann (2008) and NIOSH (2011) in that awhole module or course on safety would not be practical. Perhapsa better method would be to incorporate the hierarchy of controlsand OHS design thinking into additional courses and textbooks sothat the concepts are more integrated. A specific lecture and re-view such as performed here would then introduce and reinforcethe concepts. However, the actual integration of safe design intodiscipline specific examples and case studies may allow studentsto use what was learned and reach the learning level of conceptapplication. The results highlight the importance of continuingprofessional development in this area for practicing engineers.The education intervention could be the foundation for suchcourses.

Our assessment methods are repeatable by other researchers.All survey questions are included in the tables in the manuscript.The cases studies and proposed solutions can be found in Culvenor,2003, 1996. The educational interventions are described in detail; alink to one of the lectures is included. We encourage other engi-neering educators to utilize, repeat, improve, and tailor our workto meet their specific education outcomes. However, each univer-sity engineering program should assess the most effective way tointegrate safe design into their curriculum as there is no one-size-fits-all approach. Other researchers should consider how theycould utilize quasi or experimental research designs in future eval-uations. However, withholding or delaying a safe design interven-tion to a control group in an educational setting may be tenuousand inappropriate given the body of knowledge in this area andsafe design’s potential to positively influence worker safety andhealth.

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