Leadership Jrnl 1

7/28/2019 Leadership Jrnl 1

1/9

A comparison between two leadership models for

security checkpointsEnhancing processes by optimizing crew performance

Wetter Olive Emil, Laube Ren, & Hofer Franziska

Zurich State Police, Airport Division, Security Control

P.O. Box

CH-8058 Zrich-Flughafen (Switzerland)

[email protected], [email protected], [email protected]

AbstractThe impact of leadership structure and behavior on team

or crew performance is well known and has been demonstrated in

various studies (see e.g. Guzzo & Dickson, 1996; Zaccaro,

Rittmann, & Marks, 2001). However, as far as we know, there is no

empirical study available on leadership structures and crew

performance in the applied setting of airport security control. This

study compares the structure and impact of two different

leadership models for security control. The first (older) modelconsists of one supervisor per sector. In the supervisor's sector,

there are three to eight crews at work, each consisting of five

security officers (SOs). Each crew independently manages and

operates one line of the checkpoint. One of the five SOs in a crew is

the crew leader (CL), who works together with the crew as a

normal crew member but has a few additional tasks to fulfill. The

second (newer) model, which focuses more on integrated crew

resource management (CRM) criteria, consists of one supervisor,

assisted by two CLs per sector. Together, they form a cohesive

leading team. The CLs do not work in the crews anymore but

manage two to three lines from behind. The crews still consist of

five SOs. It is the new CLs' task to quickly isolate and manage

problematic cases so that those do not block the line anymore. Like

this, the workload of each team member is reduced. Another task is

to keep an eye on the working quality and to communicate with thecrews in such a way that working quality is enhanced. The impact

of this reinforced leadership on indicators of working quality such

as compliance with rules and regulations, as well as its impact on

passenger flow (throughput) are analyzed using different statistical

procedures such as T-tests, U-tests and Chi-square tests. Moreover,

the job models of the new leadership structure are presented in

detail and SOs' ratings of their acceptance and liking of both

systems are presented. In sum, this study offers another, different

approach to the human factors perspective in airport security

focusing on leadership structures, crew resource management, and

their effects.

Keywords-Leadership; team performance; crew performance;

security control; airport security; aviation security; crew resource

management; human factors

I. INTRODUCTION

In recent years, several terrorist attacks on civil aviation havehighlighted the needs for an effective security control. As aconsequence, large efforts have been made in this domain. It hasbecome clear that enhancing security by investing into high-techequipment such as X-ray scanners only makes sense if the human

factor is not neglected. In this field, training (e.g. X-Ray Tutor [1,2]) and competency assessment of X-ray screeners have beendeveloped and are set down in official documents (e.g. ECregulation No 2320/2002 [3]). The above mentioneddevelopments and investments in airport security focus on thesecurity officer as an individual, and, more precisely, on hisindividual performance. Undoubtedly, in this area, noteworthyimprovements have been achieved in the past. From a wide rangeof scientific publications, it is well known, however, that it is notonly the individual level of performance which determines theoverall level of performance. When crews are at work, effectssuch as social loafing (e.g. [4]) or the Ringelmann effect [5], bothof them well known to social psychologists, can occur.

Closely observing the work at the security checkpoints, aswell as analyzing results from covert tests [6] and inspections byofficials, made us speculate that SOs in crews do not tap their fullindividual potential. In other words, we had the impression thatthe overall crew performance was in some cases worse than whatthe individual best performance of a crew member would allowfor. This might hint at process losses (e.g. [7]) in the teamsituation. These insights were the main reason why we chose toopen up the perspective from the individual level to the crewlevel of performance. Up to the present, it is still unknown howbig the amount of teamwork at a security control checkpointreally is and if an analysis of and investments into crew factorsmake sense.

In order to find out more about that, we have to have a closer

look at the task itself. The task of a typical security control crewis to ensure that no forbidden articles, be it weapons or dangerousgoods, pass the checkpoint and find their way into the sterilearea. A traditional security control crew consists of five SOs atfour different positions: one person at the x-ray screen, one

978-1-4244-4170-9/09/$25.00 2009 IEEE 59


2/9

person in front of the x-ray tunnel, one person who searchessuspicious bags manually and two persons at the WTMD1. Asone can imagine, the tasks are quite different from each other.According to the typology by Steiner [8], the overall task of asecurity control crew could best be described as conjunctive.However, the individual subtasks (e.g. X-ray-screening task) canbest be described as additive. Therefore, it makes sense to have acloser look at overall team performance.

Teamwork and communication among the members of asecurity control crew become especially important in anemergency case. For example, upon detection of an improvisedexplosive device (IED), the crew has to follow a certainemergency procedure in which they can only be successful ifthey help each other and work together as a team.

Those findings encouraged thoughts about leadership modelsfor security control checkpoints. As a result of this, a newleadership model has been developed. Both the traditional andthe new model shall be explained in detail in Section II. B.Certain shortcomings, which have been noticed and attributed tosuboptimal team and leadership aspects, have been the startingpoint for the development of a new model. One of these

shortcomings is that supervisors have repeatedly reported thatthey were sure that the quality of work be lower if they wereabsent. Due to the fact that one supervisor per sector cannot bepresent throughout the whole shift (breaks, office work to bedone, etc.) and that he has a lot of other duties besides monitoringcrew performance, the logical consequence would be to installmore than one supervisor per sector in order to avoid situations inwhich no supervisor is on-site. Like this, supervisors can supportand represent each other. With adequate and well functioningleadership structures, we can also ensure that classical criteriafrom crew resource management (CRM) are met.

The importance of teamwork is well known in aviation safetyand there is also recent empirical evidence that training on CRMreally improves teamwork skills in the cockpit [9]. The term crew(or cockpit) resource management first appeared 1979 at aworkshop sponsored by NASA [10]. This was the time whenresearchers pointed out that most of the aircraft accidentsoccurred because of human errors, e.g. communication orleadership failures or errors in decision making. In this context,Reason [11-12] developed a comprehensive and systemic modelof human errors, which is also well known under the nameSwiss Cheese Model of Human Errors. According to thismodel, errors occur because of a causal chain of failures orneglects and are never a product of one single reason. In otherwords an error rarely occurs because of one single individualbut rather because of multiple circumstances. As stated above,research on human factors in airport security focused a lot on theindividual cognitive abilities and knowledge (e.g. [13-14]). A lotof very important conclusions could be drawn from such andsimilar studies. In addition to this individual approach, future

1 One female and one male in order to conduct a gender-specific

pat-down search.

research should not neglect the whole system. As Reason [12]argues, latent conditions (e.g. time pressure, structuraweaknesses of the organization, leadership and managementstyles) may lie within the system for many years before theycombine with active failures to evoke an accident opportunity. Asystemic approach, similar to that in aviation safety, shouldtherefore shape the content of future research in airport security.There lies a deep truth in the sentence We cannot change the

human condition, but we can change the conditions under whichhumans work (after [12]). Research should try to find thosefactors that make a security system or organization resilient toindividual errors. Last but not least, a live trial with the newleadership structure should yield further clues about theimportance of leadership and crew aspects at security controcheckpoints.

II. METHOD

A. Disambiguation team vs. crew

In English, the two words team and crew might both beused in order to describe the group of SOs working together at acheckpoint. In the past, several authors have sought to distinguish

between teams and crews in order to allow for an accurate, clearand consistent nomenclature.

To our understanding, the term team is broader andencompasses more different forms of groups of people than doesthe term crew. Teams can exist for several reasons, come invarious forms and sizes and can be of different longevity [15].Crews are defined in the literature by their performing ofspecialized tasks together effectively and the limited duration ofworking together [16-19]. Furthermore, they require to form andperform together immediately and effectively. They arecharacterized by high expertise, extensive training andstandardized performance guidelines, thus probably rendering agroup development process less important. Due to these findings

we would suggest that it be more accurate to talk of securitycontrol crews rather than teams. This nomenclature has beenadopted throughout this research paper.

B. Traditional vs. new leadership model

Fig. 1 shows the traditional leadership model. In thisconfiguration, there is one supervisor at work who manages onesector. In the supervisor's sector, there are about three to eightcrews at work, each consisting of five SOs. Each crewindependently manages and operates one line of the sector. Oneof the five SOs in a crew is the CL, who works together with thecrew as a normal crew member but has some additional tasks andresponsibilities to fulfill, e.g. taking over responsibility for minorproblems within the security control line or when changinglocation.

60


3/9

Sector

1 CL

4 SOs

1 CL

4 SOs

1 CL

4 SOs

1 CL

4 SOs

1 CL

4 SOs

1 Supervisor

Figure 1. Traditional leadership model.

Fig. 2 shows the new leadership model. In this configuration,there is a cohesive leading team at work consisting of onesupervisor, assisted by two CLs per sector. The main differenceto the traditional model is that the CLs do not work in the crewsanymore but manage two to three lines from behind. The crewsstill consist of five people, all of them being of equal status. It isthe new CLs' task to quickly isolate and manage problematiccases so that these do not block the line anymore. Like this, theindividual workload of each crew member should be reduced.Moreover, this reinforced leadership structure should offer better

possibilities of monitoring the security control crews' workingperformance. Because the CL is taken out of the operationalprocess of the crew, the probability of detecting failures but alsooutstanding performance should be higher compared to thetraditional model.

Figure 2. New leadership model.

C. Participants

The new leadership model is not an experiment conducted ina laboratory, but has been implemented in the daily business ofoperations. The participants were ordinary, trained SOs, CLs andsupervisors with an age range from 20 to 64 years. Thesupervisors have been selected especially for this new taskamong the pool of supervisors, whereas all the other staff havebeen assigned to crews and checkpoints as usual. Staff involved,

as well as their assignment to crews, changed on a daily basis.Crews always consisted of males and females. Overall, the totalnumber of females was higher than that of males.

D. Statistical analyses

Apart from descriptive statistics, several other statisticaprocedures have been applied in order to assess if the obtainedresults are significant. T-tests (both one- and two-tailed) havebeen used to compare means, U-tests have been used to compareranks and Chi-square tests have been used to comparefrequencies. The methods used are presented in more detail in thestandard literature on statistics (e.g. [20]).

III. PROCEDUREANDMATERIALS

The new leadership model described in Section II. B. hasbeen put in place between March 11th and April 7th, 2009Evaluations started not until March 20th in order to give the staffenough time to become reasonably familiar with the new modeland the slightly different tasks. Evaluations took place on fourdays when the new leadership model was either active or not. Allevaluations that later involved a comparison of data between thetwo leadership models took place in the same sector. Evaluationtimes consisted of phases with high passenger volume (rush-hour) as well as phases with low passenger volume.

The field of interest encompassed a comparison of both

leadership models using objective and subjective measuresQuality of work as well as passenger throughput could bemeasured using objective indicators. Moreover, the different jobprofiles of supervisors in the traditional and the new leadershipmodel were determined by observation as well. On a subjectivelevel, the staff rated the perceived quality of work, currentsatisfaction with work and working atmosphere. Moreover, thestaff indicated their liking of both leadership models in acombined scale. All staff working in the sector have beenevaluated (population level) except for the evaluations of thequality of work and the CL's job models. In these domainssamples had to be evaluated due to limitations in the amount ofavailable personnel for observation.

Quality of work was operationalized for both observation andrating as compliance with internal and external regulationsThroughput was operationalized as how many passengers passedthe Walk-Trough-Metal-Detector (WTMD) per hour. Job profileshave been defined by the management on setting up the newleadership model and have been observed during the dailyoperation accordingly.

IV. RESULTS

A. Job profiles

It can be expected that supervisors' and CLs' job profileschange along with the new leadership structure. In order to assess

job profiles, the tasks to be fulfilled have been analyzed andassigned to categories. Table I shows the category names as wellas the tasks that are covered by the respective category. Ondesigning the new leadership structure, the management set up ajob profile for the new leading team that forecasts how muchtime might be invested for the different task categories (Fig. 3).

Sector

5 SOs 5 SOs 5 SOs 5 SOs 5 SOs

1 Supervisor

1 CL 1 CL

61


4/9

TABLE I. CATEGORIESANDTASKSCOVERED

Category Tasks covered

ManagementObserving the situation, controlling,correcting and praising SOs

Collaboration Working with and helping crews

Briefing Briefing

Taking over on request Taking over a case on SO's request

Taking over on owninitiative

Taking over a case spontaneously and onown initiative

Open tests

Carrying out open tests with SOs. An open

test consists of an interview, in which a SO is

asked to explain the content of an x-ray

image of a bag

43%

13%

13%

13%

13%

8%

Management Collaboration Briefing

Taking over onrequest

Taking over onown initiative

Open tests

Figure 3. Job profile forecast.

As can be seen, most of the time was expected to be spent formanagement tasks such as keeping an eye on the working qualityin the sector, communicating with crews in order to keep themmotivated and providing them feedback on their work. As aninnovation, the leading team should conduct open tests with theircrews during phases with low passenger volume (see Table 1 formore details on the procedure of an open test).

In the daily operation, the actual job profile (Fig. 4) has beenassessed during 267 min. of observation, both in phases with highand low passenger volume. Interestingly, much more time thanpredicted has been spent for management tasks. Raters had theimpression that especially at times with low passenger volume,some members of the leading team have been idle rather thanusing this time for briefings, instructions, open tests, etc. As a

consequence of this, no open tests have taken place during thetime span evaluated. Moreover, it can be noted that the time spentfor dealing with cases is much lower than predicted by themanagement. This might have several reasons: For example,there could have been less cases than expected or the leading

team might not have been called for assistance as often aspredicted.

75%

12%

7%

2% 4%




Open tests

Figure 4. Actual job profile.

As mentioned earlier, changing the leadership model alsomeans a change in the responsibilities and tasks to be fulfilled bythe leading team. Due to this, the traditional job models of theCLs (Fig. 5) and supervisors (Fig. 6) have been assessed as well.

3%

97%

1%




Open tests

Figure 5. Traditional CL job profile.

62


5/9

72%

11%

10%

4% 3%




Open tests

Figure 6. Traditional supervisor job profile.

On comparing Fig. 4 with Fig. 5 or Fig. 6 respectively, itbecomes clear that there would be no big change for supervisorsin case the new leadership model should be adopted in the future.For CLs, however, there will be a big change in their daily work.They will no more spend most of their time working in the crewlike an ordinary SO, but will dedicate a big amount of their timefor management tasks. This might hint at the necessity forparticularly preparing, instructing and training the CLs for thenew tasks.

B. Quality of work objective data

In both the old and the new leadership model, the number ofrandom pat-down searches of passengers was measured. Since apassenger cannot predict whether he will be subject to a pat-down search or not, the higher the number of random pat-downsearches, the better for the quality of work with regard tosecurity. In order to be compliant with the current regulation,SOs partly rely on technical equipment (the quota alarm of theWTMD) and partly on their own feeling in order to select therequired number of passengers for an additional pat-down search.Fig. 7 shows the rate of random pat-down searches in bothleadership models. In the new leadership structure, more2 randompat-down searches have been carried out compared to the oldleadership structure. This result is in keeping with thehypotheses. A one-tailed T-test reveals a significant result witht(13) = 2.06, p < .05. This implies that the quality of work washigher in the new leadership structure.

2 Since all numbers are considered security sensitive

information, they are not indicated throughout this paper.

Old New

Leadership structure

%P

AX

p< .05

Figure 7. Random pat-down search rate (means and standard deviations).

As described before, SOs partly rely on technical equipment(the WTMD) to select a passenger for a pat-down search. Onconducting this study, we assumed the number of selected peopleby the WTMD be equally distributed in the new and oldleadership model. On having a closer look at the data, we foundout that this was probably not the case. Fig. 8 shows that therandom alarm of the WTMD appears3 to have been higher duringthe evaluation phase of the new model.

Old New

Additional body

search inde-

pendent of quo-

ta or metal

alarm

Quota alarm of

WTMD


%P

AX

Figure 8. Random pat-down search rate for quota alarms (WTMD) and

manually selected passengers separately.

There seems to be no difference between the number of

manually selected passengers in both leadership models3

, i.e. therate of manually selected passengers appears to be independentof the number of technical alarms. Taking into account that the

3 No statistical analyses have been calculated due to too low

numbers within cells.

63


6/9

technical alarm rate seems to have been higher during theevaluation of the new leadership model, one can argue that SOsdid not compensate this higher rate of technical alarms. This canbe interpreted as an increase in working quality: although thetechnical alarm rate appears to have been higher, the manuallyselected number of passengers appears not to have decreased inthe new model.

Different internal process instructions are to be followed

depending on the alarm a passenger raises on passing theWTMD. It has been analyzed how well these differentinstructions are followed by the SOs. As can be seen in Fig. 9,compliance with WTMD process instructions is significantly

better in the new leadership model than in the traditional one (2

(1,N= 173) = 4.94,p < .05).

Old New


%c

orre

ct

p< .05

Figure 9. Rate of correctly following WTMD process instructions.

Last but not least, it has been evaluated whether the correct

procedures for manual cabin baggage search have more closelybeen followed in the new leadership model than in the traditionalone. However, this has not been the case: there have been no

significant differences (2 (1,N= 180) = 0.29,p = .59).

C. Quality of work subjective ratings

Right after the analyses stated in Section IV. B., all SOs ofthe respective sector (N = 41) have been asked to provide ratingsof the current working quality at the place on a scale from 1 (verypoor) to 6 (excellent). Like this, objective data and subjectiveimpressions can be directly compared. Ratings in the traditionaland the new leadership model do not significantly differ fromeach other (U= 167.50,p = .21). This means, that the SOs do notthink that the working quality is higher in the new leadership

model than in the traditional one. However, the objective datastated in Section IV. B. show an advantage of the new modelover the traditional one. Apparently, the SOs do not notice thisdifference. They either underestimate the working quality of the

new model or they overestimate the working quality of thetraditional system.

At the same time, supervisors have been asked to provideratings as well. On a scale from 1 (very poor) to 6 (excellent),they rated the overall working quality in the sector, as well as theworking quality concerning the WTMD and the carry-onbaggage in particular (Fig. 10).

Overall WTMD Carry-on baggage

1

1.5

2

2.5

3

3.5

4

4.5

5

5.5

6

Old structure New structure

Quality

Figure 10. Supervisors' ratings of quality of work (means and standarddeviations).

It becomes clear that supervisors are somewhat less optimisticabout the quality of work than the SOs. There are severapossible reasons for this finding. It might be the case that thesupervisors are in general more pessimistic and have higherlevels of aspirations than the SOs. To us, this appears to beunlikely based on our personal experiences. The more likelyexplanation seems to be that the supervisors have an overview ofthe checkpoint processes from outside and are thus more likely toget a realistic and accurate view of the quality of work. Howeverthat remains to be proven in detail.

D. Employee satisfaction and model preferenceOne of the most important aspects for the implementation of a

new leadership model is its acceptance among the employees. Ifa model has too little support, it can be expected that the qualityand the amount of work decrease and absenteeism increases. Dueto that, it has been evaluated how good the reputation of the newleadership model is among the employees.

Firstly, the employees' present satisfaction of work has beenassessed in the traditional and the new leadership model. A totalof 41 employees rated their current satisfaction on a scale from 1(very poor) to 6 (excellent) (Fig. 11). The current satisfaction ofthe employees working in the new leadership model (M= 4.90SD = 0.77) is higher than the one of the employees working in

the traditional model (M= 3.57, SD = 1.04). In a two-tailed t-testthis result is significant with t(36.83) = 4.66,p < .001. Howeverwith this study, it cannot clearly be determined to what this effeccan be attributed. Most likely, it has to do with the leadershipstructure. It cannot be ruled out, however, that the supervisors inthe new system managed to create a better atmosphere (e.g. they

64


7/9


8/9

working quality in the new model. We also found that internalprocess regulations at the WTMD were more closely followedthe new model. Here, a significantly higher standard could beobserved in the new leadership model. However, we found noeffect of the leadership model on the quality of the hand search ofcabin baggage. Although still to be considered as first results,they all point in the same direction and indicate that the newleadership model influences working quality and security level in

a rather positive way. In our view, it is important that alongitudinal study replicates these first tentative results.

Rather unexpectedly, it has turned out that SOs seem tooverestimate the working quality at their workplace. Only thesupervisors in the new leadership model have been able to gain asomewhat more realistic view on this subject. This might hint atthe necessity of having have enough personnel (supervisors)behind or outside the control lines in order to constantly monitorworking quality and compliance with process instructions. Thisalso reflects our personal experiences, which are based on manydiscussions with SOs: Standing behind or outside the securityprocess is totally different compared to working within a crew ata specific position. It is not possible to get a comprehensive orrather holistic impression of the security control process if one is

an active part of it. Furthermore, working within a crew at thecheckpoint can be stressful and there might not be any cognitiveresources left for observing the whole process.

It could be argued that employees would not accept such aclose monitoring of their work. Contrary to such expectations, wehave found that the employees' satisfaction with the currentworking situation was even better in the new leadership model.On directly asking employees to indicate how much they like thetwo systems in comparison to each other, it turns out that thereexists no overall preference for either system. Taking intoaccount the human tendency to rather stick with what is wellknown and familiar, this is no bad result at all and as such ratherspeaking for the new model. Monitoring activities do not have to

have a negative connotation. Without any monitoring orcontrolling, good or outstanding work would never be detected.This is another argument for the presence of enough supervisorson-site.

We have not been able to find an overall effect of the newleadership model on facilitation in terms of passengerthroughput. It is a good sign that the new leadership model, inwhich more pat-down searches have been done and which theSOs were not at all used to, provided no lower figures forthroughput than the well-known traditional model. Moreover,caring for high throughput had not been declared as a goal toneither the SOs nor to the supervisors. Longitudinal studies couldclarify whether the new leadership model increases throughput inthe long term. In future research, it should also be kept in mindthat on assessing performance and maybe also working quality, aHawthorne effect [21] is very likely to occur.

On assessing the amount of change which the new leadershipmodel would bring to the supervisors' and CLs' daily routine, it

was found that the supervisors' job would not change that muchTheir new job profile would look quite similar to the one theyhad up to now. For the CLs, however, there would be majorchanges. They would no more be working in the crews bumonitor the situation from the outside. As a consequence, theirjob profile would contain much more leadership tasks than up tothe present. In our view, this change in job profiles would justifya new selection process for the future CLs. Selection criteria

might be different (e.g. focusing more on leadership qualities)from the ones that are applied up to now. There is still some workto be done on what the new selection criteria should look like andwhat they should consist of.

The present study is an applied study which has been carriedout at an airport during daily business. In comparison with alaboratory study, this offers much more insights into the practicalaspects such as feasibility and acceptance by the employeesMoreover, we have been able to run some analyses on thepopulation level (assessing all SOs working in the respectivesector), which is certainly an advantage compared to the use ofsamples, which is the case in most laboratory studies. On theother hand, we also have to openly acknowledge someshortcomings of this first study. In some analyses, it cannot be

proved if the positive effect found is attributable to the leadershipstructure alone. We for example cannot completely rule outalternative explanations for the positive effects found on currentemployee satisfaction and working quality.

Bearing these shortcomings in mind, we would like toconclude that it makes sense to think about leadership aspects atsecurity checkpoints. This study hints at the possibility ofpositive effects of leadership structure on variables such asworking quality, security level, and employee satisfaction. Morework will be done in the near future in order to understand moreabout the impact of leadership aspects at security controcheckpoints.

REFERENCES

[1] Schwaninger, A. (2003c). Training of Airport Security Screeners. Airport05, 11-13.

[2] Schwaninger, A. (2004b). Computer based training: a powerful tool to theenhancement of human factors. Aviation Security International, FEB/200431-36.

[3] European Parliament and Council (2002). Regulation (EC) No 2320/2002of the European Parliament and of the Council of 16 December 2002establishing common rules in the field of civil aviation security. OfficialJournal of the European Communities.

[4] Karau, S.J., & Williams, K.D. (1993). Social loafing: A meta-analyticreview and theoretical integration. Journal of Personality and SociaPsychology, 65, 681-706.

[5] Ingham, A.G., Levinger, G., Graves, J., & Peckham, V. (1974). TheRingelmann Effect: Studies of group size and group performance. Journal

of Experimental Social Psychology, 10, 371-84.[6] Wetter, O.E., Hardmeier, D., & Hofer, F. (2008). Covert Testing a

Airports: Exploring Methodology and Results. Proceedings of the 42ndCarnahan Conference on Security Technology, Prague, October 13-162008.

66


9/9

[7] Nijstad, B.A., & van Knippenberg, D. (2007). Gruppenpsychologie:Grundlegende Prinzipien. In K. Jonas, W. Stroebe, & M. Hewstone (Eds.),Sozialpsychologie (5th ed.). Heidelberg: Springer.

[8] Steiner, I.D. (1972). Group process and productivity. New York: AcademicPress.

[9] Salas, E., Fowlkes, J.E., Stout, R.J., Milanovich, D.M., & Prince, C.(1999). Does CRM Training Improve Teamwork Skills in the Cockpit?Two Evaluation Studies. Human Factors: The Journal of the HumanFactors and Ergonomics Society, 41(2), 326-343.

[10] Cooper, G.E., White, M.D., & Lauber, J.K. (1980). Resource Managementon the Flightdeck: Proceedings of a NASA/Industry Workshop. (NASACP-2120). Moffett Field, CA: NASA-Ames Research Center.

[11] Reason J. (1990). Human error. New York: Cambridge University Press.

[12] Reason, J. (2000). Models and management. BMJ, 320, 768-770.

[13] McCarley, J.S., Kramer, A.F., Wickens, C.D., Vidoni, E.D., & Boot, W.R.(2004). Visual skills in airport security screening. Psychological Science,15, 302-306.

[14] Schwaninger, A., Hardmeier, D., & Hofer, F. (2005). Aviation SecurityScreeners Visual Abilities & Visual Knowledge Management. IEEE A&ESystems Magazine, June 2005, 29-35.

[15] Cohen, S.G., & Bailey, D.E. (1997). What Makes Teams Work: GroupEffectiveness Research from the Shop Floor to the Executive Suite. Journalof Management, 23(3), 239-290.

[16] Arrow, H., McGrath, J.E., & Berdahl, J.L. (2000). Small Groups asComplex, Systems: Formation, Coordination, Development, andAdaptation. Thousand Oaks: SAGE Publishing Co.

[17] Arrow, H., & McGrath, J.E. (1995). Membership Dynamics in Groups aWork: A Theoretical Perspective. In B. Staw, & L. Cummings (Eds.)Research in Organizational Behavior (vol. 17). New York: JAI Press.

[18] Ginnett, R.C. (1993). Crews as groups: Their formation and theileadership. In E.L. Wiener, B.G. Kanki, & R.L. Helmreich (Eds.), CockpitResource Management. San Diego: Academic Press.

[19] Kozlowski, S.W.J., & Bell, B.S. (2003). Work groups and teams inorganizations. In W.C. Borman, D.R. Ilgen, & R.J. Klimoski (Eds.)Handbook of psychology: Industrial and organizational psychology (vol12). London: Wiley.

[20] Sirkin, R.M. (2006). Statistics for the Social Sciences. Thousand OaksSAGE Publishing Co.

[21] Landsberger, H.A. (1958). Hawthorne revisited: Management and theworker: its critics, and developments in human relations in industry. IthacaCornell University.

67

Documents

Leadership Jrnl 1