5-Mohammadfam

JRHS 2008; 8(1): 33-38

Copyright © Journal of Research in Health Sciences

The Application of Human Factors Engineering for Evaluation of Overall Performance

Mohammad Fam I (PhD)

Department of Occupational Health, Faculty of Health, University of Hamadan Medical Science, Hamadan, Iran

*Correspondence: Iraj Mohammadfam, E-mail: Fam@engmail.ut.ac.ir

Received: 2 July2007; Accepted: 19 December 2007

Abstract

Background: Total system design (TSD) factors are design factors, which have impact on overall performance of the power plants in context of total human engineering or macroergonomic. The evaluation of the impact of TSD factors was the main goal of this study. The main objective was human factors engineering on human performance in a power plant.

Methods: The systems being studied are the control rooms and maintenance departments of a 2000 MW thermal power plant in IRAN. By non-parametric correlation analysis and Kruskal-Wallis test of means, we can achieve between TSD factors and human performance.

Results: The selected TSD factors are related to procedures, work assessment, teamwork, self-organization, information exchange and communication. In a way we can say that various factors influence on human performance in the power plant is TSD factors such as organizational and safety procedures, teamwork, self-organization, job design and information exchange.

Conclusion: The best way to increase human performance is TSD factors must be considered, designed and tested concurrently with the engineering factors at the design phase of the system developmental cycle.

Key words: Ergonomic, Human, Performance Power plants, Safety

Introduction

Total system design (TSD) is an integrated de­velopmental process, based on a series of well-defined phases. Frequently in the past, de­signers used other approaches without giv­ing much attention to human performance. TSD requires equal consideration to all ma­jor components of the system such as hu­man, hardware, software and organizational structures. Indeed, it is quite important to pay serious attention to human and organiza­tional aspects of the TSD process from early design phase.

TSD factors in context of human perform­ance are referred to as socio-technical factors in context of system design. It should be noted that the engineering design process is of­ten perceived as mainly technical activity, yet within engineering design organization it really only coheres as a social activity. This pa­per introduces the socio-technical factors as essential and vital part of the design proc­ess in power plants and because they are re­lated to overall management and organiza­tion structures, they are referred to as TSD factors in context of human performance (1-3).

TSD factors in context of human perform­ance define the macroergonomics features of the system design and human performance en­gineering, whereas, the conventional sys­tem design factors in context of human per­formance define the ergonomics features of the system design and human performance en­gineering. Macroergonomic and the con­cept of total human factors were developed by Hendrick and Meshkati and elaborated by other researchers (4-10).

Ergonomic attempts to optimize the interac­tion between human operator and machine. It considers those factors of machine, design and work posture that affect the user inter­face and working conditions related to the job or task deign. In a macroergonomics study, the ergonomics factors are considered in parallel to organizational and managerial as­pects of working conditions in context of a total system design. Moreover, it attempts to create equilibrium between, organization, op­erators and machines. It focuses on total "people-technology" systems and is con­cerned with the impacts of technological sys­tems on organizational, managerial and person­nel subsystems (11-13).

Macroergonomic adopts a more holistic ap­proach to human factors' problems of manu­facturing systems. It considers the whole and avoids the trap of dealing with specialties with which we feel comfortable. A macroergo­nomics program optimizes inter­face between operators, machines and organi­zation by using teamwork, on-the-job training, welldefined procedures and total management.

Methods

TSD factors in context of human perform­ance are defined as factors influencing total system's performance such as rules and proce­dures and information exchange be­tween personnel/departments. To measure the impacts of TSD factors on human perform­ance, a questionnaire was designed and handed out to all control room and mainte­nance operators. It was designed based on total system design aspects of hu­man performance in power plants. More­over, key macroergonomics factors were in­cluded to evaluate human performance. The selected TSD factors are related to proce­dures, work assessment, teamwork, self-organi­zation, information exchange and com­munication. They were inputted to the questionnaire and their statistical relation­ships to the human performance were exam­ined through two non-parametric statistical (namely, Cramer's Phi and Kruskal-Wallis) ap­proach. The selected TSD factors in con­text of human performance were tested in the following format:

1. Degree of familiarity with rules and proce­dures

2. Supervisors' monitoring and assessment at work

3. Reward for teamwork by supervisors

4. Ease of contact with supervisors

5. Problems with co-workers due to inter-or­ganizational relationship

6. Quality of perceived information from su­pervisors

7. Quality of perceived information from co-workers

8. Usefulness of informal information ex­change

9. Freedom for self-organized and individual decision-making

As mentioned, a set of non-parametric test of hypothesis is conducted to foresee if human performance is independent of the selected TSD factors. Furthermore, job pressure is se­lected as the factor representing human per­formance since it is identified as one of the most important human shaping factors. The sources of job pressure in the power plants are classified as 1) workload 2) stress and 3) time considerations. Because workload is iden­tified as the most influential source of job pressure, it is selected as the measure of human performance in this study. It is tested whether job pressure due to workload is influ­enced by the TSD factors. In addition, the difference between mean ratings of opera­tors in respect to selected TSD factors are examined through Kruskal-Wallis test. For example, the operators who can easily communicate with supervisors are compared with the ones who cannot easily communi­cate with supervisors in respect to the level of job pressure.

The systems being studied are the control rooms and maintenance departments of Sh. Rajaeil power plant in Ghazvin- Iran. The plant was provided with dry cooling system (Heller), the power evacuated from the 400kV switchyard, and all the units are in op­eration. The number of company's staff was 472.

Results

The Cramer's Phi statistic tests the null hy­pothesis (H0) of no correlation between the two variables against alternative hypothesis (H1) of correlation between the two vari­ables. The test of hypothesis is in the follow­ing general format:

H0: The TSD factors are not correlated with job pressure due to workload

H1: Otherwise

As shown in Table 1 there is strong evidence that the nine TSD factors are correlated with the job pressure at work. Furthermore, the job pressure at work is influenced by fa­mili­ar­ity with organizational rules and proce­dures and information flows between co-workers, co-workers, and supervisors. In addition, job pressure is positively correlated with team­work. Operators who are rewarded for team­work report lower level of job pres­sure and consequently produce higher perform­ance. The freedom for self-organiza­tion is posi­tively cor­related with human per­formance. In sum­mary, these findings sug­gest the positive im­pacts of TSD factors on human performance (Table 1).

Table 1: Test of correlation between human performances (job pressure) and the selected TSD factors

TSD factor

Cramer's Phi

P- Value (α)

1. Degree of familiarity with rules and procedures

.63

.00070

2. Supervisors' monitoring and assessment at work

.44

.00010

3. Reward for teamwork by supervisors

.51

.00310

4. Ease of contact with supervisors

.48

.00002

5. Problems with co-workers due to inter-organizational issues

.57

.00040

6. Suitability of perceived information from supervisors

.49

.00110

7. Suitability of perceived information from co-workers

.41

.00040

8. Usefulness of informal information exchange

.53

.00010

9. Freedom for self-organized and individual decision-making

.44

.00030

To further investigation, series of compara­tive studies are performed between various groups of operators in the next section. It is ex­amined if TSD factors influence the hu­man performance in particular and the sys­tem in general. To achieve this objective, two groups of operators are examined on the selected response variables. The selected re­sponse variables are the quality of informa­tion perceived from supervisors and co-work­ers and job pressure. The Kruskal -Wal­lis test performs an analysis that is very simi­lar to an analysis of variance (ANOVA) on the ranks. The test is conducted when the as­sumptions for the parametric ANOVA can­not be made (14). Furthermore, it assumes in­dependence between subjects in condi­tions. This test also acts as verification and validation process of the previous test and al­most the same types of results are reported in different format. The general format for the test is as follows:

Ho: The two groups of operators have the same performance with respect to the re­sponse variable, where the response vari­ables are the quality of perceived informa­tion from supervisors and co-workers and job pressure.

H1: Otherwise

In job pressure, two major types of operators exist in which those operators who cannot eas­ily communicate with supervisors report higher level of job pressure. Operators who can easily communicate with supervisors re­port higher quality of perceived information from super­visors. Operators who believe that there could be a better job design reported higher level of job pressure.

The last column in Table 2 and 3 define the relative advantage of group 1 over group 2 in relation to the quality of information per­ceived from supervisors and co-workers, re­spec­tively. Furthermore, the relative statisti­cal advantage of group 1 over group 2 is tabu­lated by the percent increase in quality of information per­ceived from supervisors and co-workers, re­spectively. The last col­umn in Table 3 de­fines the relative advan­tage of group 1 over group 2 in relation to the job pressure. The significant difference between the groups of operators who are util­izing the TSD factors and the groups who are not with respect to the response variables reveal that TSD fac­tors extensively influence the human per­form­ance in particular and the system in general.

Table 2: The significant level of test of comparison on the quality of information perceived from supervisors

Difference in mean ranking

P- Value (α)

Relative advantage (%)

Group 1

Group 2

With on-thejob training

Without on-the-job training

0.0516

30

No problem with organizational procedures

Having problems with organizational procedures

0.0020

60

Rewarded for teamwork

Not rewarded for teamwork

0.0031

40

With individual decision-making capability

Without individual decision-making capability

0.0154

30

Can easily communicate with supervisors

Cant easily communicate with supervisors

0.0113

40

No problem with co-workers due to inter-organizational issues

Having problems with co-workers due to inter-organizational issues

0.0131

32

Table 3: The significant level of test of comparison on the job pressure

Difference in mean ranking

Significant level (α)

Relative disadvantage

(%)

Group 1

Group 2

Can easily communicate with supervisors

Cant easily communicate with supervisors

0.0053

58

Believing a better job design is required

Believing current system is ok

0.0021

300


The Kruskal-Wallis test of comparison be
­tween the two groups verifies and validates the previous results obtained from the test of correlation between TSD factors and job pres­sure.

Discussion

The conventional design approach in power plants considers the engineering design pa­rameters and ergonomics factors (in some cases). However, the TSD approach of this study in context of human performance consid­ers the engineering design parameters and macroergonomics factors. The impacts of TSD factors on human performance showed in Table 1. This table shows through design and evaluation of a detailed survey con­taining information about TSD factors and human performance. It had been showed that a total system design approach in con­text of human performance is much more effi­cient than a conventional design ap­proach. This is shown through introduction of the TSD model, applying the model in a power plant and showing its advantage through statistical analysis.

Non-parametric statistical analyses were used to show positive correlation between hu­man performance and TSD factors and to highlight the impact of TSD factors on hu­man performance. Furthermore, it is noted that by designing and implementing a TSD ap­proach, the system and its human element are totally rather than locally optimized in con­text of human performance.

It should be noted that the conventional de­sign approach in context of human factors is only capable of identifying local or station­ary human performance issues. This study showed that the employment of a TSD ap­proach is superior to conventional design ap­proach.

The findings of this study have several de­sign implications. Rules and procedures, infor­mation exchange between personnel (op­erators and supervisors) teamwork and self-organization may be designed and accom­modated through standardization of the documentation process and automated tracking systems. This may be achieved through:

  1. Implementation of ISO 9000 series of standards to promote standardization of docu­mentation (rules, procedures, guidelines and communications) process.
  2. Implementation of ISO 14000 series of standards to promote standardization of docu­mentation process for environmental man­agement systems.
  3. Implementation of OHSAS 18000 to de­velop standardization of documentation proc­ess for safety management and occupa­tional hygiene systems.
  4. Design and implementation of automated information exchange in context of informa­tion technology. This would facilitate and en­hance the existing information structure.

Design and implementation of the re-engineer­ing concept may enhance organiza­tional relationships and surveillance. Re-engi­neering is the collection of activities and mechanisms required changing from hierarchi­cal to horizontal, flat and cross-func­tional structures based on teamwork within an organization. The main goal in such program is customer's satisfaction. More elaboration on the scientific tools for im­plementation of TSD factors in context of human performance is left for a full research paper in the future 

Acknowledgements

We gratefully acknowledge MAPNA groups for supporting this research financially.

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