also depended on users' perceptions of the physical work practices in an office landscape. In W. Mitchell,. Ed., Environmental Design: Research and Practice.
Journal of Environmental Psychology (1997) 17, 69–74 1997 Academic Press Limited
0272-4944/97/010069+6$25·00/0
Journalof
ENVIRONMENTAL PSYCHOLOGY
EMPIRICAL VALIDATION OF A MODEL OF USER SATISFACTION WITH BUILDINGS AND THEIR ENVIRONMENTS AS WORKPLACES ´
´
´
MARIA SOLEDAD RODRIGUEZ GONZALEZ*, CONSTANTINO ARCE FERNANDEZ*
AND
´ JOSE MANUEL SABUCEDO CAMESELLE†
*Department of Methods and Research Techniques, †Department of Social Psychology, University of Santiago de Compostela, Spain
Abstract This paper reports the results of a study to validate, using LISREL, a structural model relating dimensions characterizing the user’s perception of buildings (evaluation, temperature, noise, air and space) to user satisfaction with those buildings and their environments as workplaces. Eighty-three lecturers, students and administrative staff at the Psychology Faculty of the University of Santiago de Compostela (Spain) were administered an ad hoc 13-item questionnaire on their perception of, and satisfaction with, the faculty building. The model fitted the data satisfactorily. User satisfaction with the building was best predicted by affective evaluation; the physical dimensions of perception were much less determinant. 1997 Academic Press Limited
Introduction Within the field of environmental psychology, increasing attention is being paid to post-occupancy evaluation (POE) defined by Zimring and Reizenstein (1980) as “the examination of the effectiveness, for human users, of occupied designed environments”. In contrast to experimental research on the behavioural effects of environment, POE studies are descriptive field studies of welldefined environments “such as highrise housing, commercial offices, city parks or academic institutions” which are the setting with which human users interact. POE studies of buildings as workplaces (which have mainly concerned office buildings) have largely concentrated on determining users’ attitudes to, and satisfaction with, certain attributes, of the buildings in question (Brookes, 1972; Davis, 1972; Farrenkopf & Roth, 1980; Zimring, 1990). However, the individual’s perception of his or her environment has affective as well as perceptive–cognitive aspects (Ward & Russell, 1981). The initial affective response to a building, for example, will treat it as nice or nasty, pleasant or unpleasant, etc. Empirical studies of this affective response in relation to Osgood et al.’s (1957) three-dimensional theory of
attitudes have suggested that it is in fact characterized by just one of his three dimensions. Evaluation, and that the emotional reaction to the environment—buildings in particular—is the central component of environmental perception. By contrast, the perceptive–cognitive response to a building creates a denotative rather than a connotative description by reference to its physical characteristics (Stokols, 1978); studies of this aspect find that the basic dimensions of the individual’s awareness of a building’s objective properties are Temperature, Space, Noise, Air and Illumination (Gifford, 1987; Vischer, 1989). Curiously, the affective and perceptive–cognitive aspects of environmental perception have rarely been studied jointly. However, in previous work by this group we developed a questionnaire covering both these aspects: an initial set of 21 items was reduced, on the basis of successive exploratory factor analysis, to a 10-item questionnaire in which the five dimensions Evaluation, Temperature, Noise, Air and ´ Space are each measured with two items (Rodrıguez, 1994). The final 10-item questionnaire has good internal consistency (0·8529) and satisfactory construct validity (the same factor structure emerged, regardless of whether Osgood or Likert ´ scales were used for item responses; Rodrıguez,
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1993). The nonemergence of Illumination as a clearly defined dimension was not unexpected, since it was also relatively ill defined in Vischer’s (1989) study; Vischer suggested that users may not be the best judges of their lighting conditions. Our finding ´ (Rodrıguez, 1994) that most variance in user perception of buildings was explained by the global Evaluation dimension corroborated the opinion that emotional response is central to environmental awareness (Russell et al., 1981); the less explicative dimensions measuring subjective perception of physical properties are sometimes referred to as the secondary dimensions of environmental representation. Among the many aspects of job satisfaction as a global measure of the quality of working life (Landy & Trumbo, 1976; Locke, 1983; Sundstrom, 1986) is the worker’s satisfaction with his or her physical environment (Langdon, 1966; Lunden, 1972; Harris & Associates, 1978; Renwick & Lawler, 1978). In this work we evaluated a structural model explaining user satisfaction with buildings and their environments as workplaces (henceforth “Satisfaction”) in terms of the user’s perception of the building as characterized by the dimensions of the questionnaire described above.
Method Subjects and setting The subjects taking part in the study were 83 volunteers (41 males, 42 females; age 30·06±8·45 years, range 18–58 years), all of whom were users of the Psychology Faculty building at the University of Santiago de Compostela (Spain) as lecturers (30), students (30, six from each year of the 5-year
course) or administrative staff (23, the entire complement of the faculty). The three user groups had matching sex distributions. The building consists of three floors and a basement. The first and second floors have individual offices for professors and rooms for seminars. The lower floor is occupied by lecture rooms, with capacities for between 80 and 150 students. Finally, the basement has both laboratories and offices for professors. All of the elements of the building have natural light and ventilation. The building is within the campus of the University of Santiago, away from the city centre and surrounded by wide green spaces. Instruments and procedure Subjects’ perceptions of and satisfaction with the Psychology Faculty building were measured by means of a single two-part questionnaire; the first part consisted of the 10-item user perception ques´ tionnaire developed previously (Rodrıguez, 1994), and the second part measured user satisfaction with: (1) the environment surrounding the building; (2) the building as a place of work; and (3) the building used by himself or herself in comparison with the other buildings on the university campus. User perception items were responded to on a 5-point Likert scale ranging from “strongly disagree” (1) to “strongly agree” (5); user satisfaction items were responded to on a 7-point Osgood scale ranging from “dissatisfied” (1) to “satisfied” (7). The whole questionnaire is shown in Table 1. It was administered to the subjects individually, always with the same instructions and by the same researchers; half the subjects answered the Part I (user perception) items in the order shown in Table 1, and half in the reverse order.
TABLE 1. The questionnaire used, together with the names used in Figure 1 for each item 1. The building is well insulated thermally 2. Space is well distributed 3. The building has good ventilation 4. The building is pleasant to be in 5. The building is quiet 6. There is sufficient room 7. The temperature is comfortable 8. The soundproofing is good 9. The building is aesthetically pleasing 10. The air is fresh What is your general degree of satisfaction with the surroundings of the Faculty building? What is your degree of satisfaction with the Faculty building as a place to work or study? What is your degree of satisfaction with this Faculty building in comparison with other faculty buildings on this campus?
(Insulation) (Distribution) (Ventilation) (Pleasantness) (Noisiness) (Spaciousness) (Temperature) (Soundproofing) (Aesthetics) (Air quality) (Surroundings) (Building) (Relative satisfaction)
Empirical Validation of a Model of User Satisfaction With Buildings
71
λx X1
Pleasantness
X2
Aesthetics
X3
Insulation
ξ1
1.000
EVALUATION
γ
0.655
ξ2
1.000
1.000 TEMPERATURE
X4 X5
Temperature
0.162
NOISE X6 Soundproofing X7
0.769
Ventilation Air quality
Building
Y2
0.568
Relative Satis.
Y3
0.073
AIR X8
Y1
0.597
SATISFACTION
0.047
ξ4
1.000
Surroundings 0.475
η
ξ3
1.000
Noisiness
λy
0.156
0.509
0.830
X9 Spaciousness
ξ5
1.000
SPACE X10 FIGURE 1.
Distribution
0.307
The model tested, with relation-lines labelled with the estimated values of the corresponding parameters.
Description of the model The model evaluated (Figure 1) consists of a) a structural equation for the linear dependence of the latent variable Satisfaction (η) on the five independent latent variables characterizing user percep-
tion: Evaluation (ξ1), Temperature (ξ2), Noise (ξ3), Air (ξ4) and Space (ξ2); and (b) measurement models relating the observed variables (the questionnaire items scores) to the corresponding latent variables (the dimensions the items measure). Following LISREL convention, observed variables measuring
TABLE 2. Means and standard deviations of the observed variables, and the corresponding correlation matrix variables Satisfaction Y1. Surroundings Y2. Building Y3. Relat. Satisfaction Evaluation X1. Pleasantness X2. Aesthetics Temperature X3. Insulation X4. Temperature Noise X5. Noisiness X6. Soundproofing Air X7. Ventilation X8. Air quality Space X9. Spaciousness X10. Distribution Means S.D.
Y1
Y2
Y3
X1
X2
X3
X4
X5
X6
X7
X8
X9
X10
— 0·514 — 0·461 0·649 — 0·544 0·658 0·670 — 0·361 0·406 0·454 0·655 — 0·403 0·287 0·254 0·331 0·196 0·203 0·142 0·082
0·307 0·024
— 0·501 —
0·312 0·304 0·267 0·387 0·233 0·236 0·374 0·385
0·205 0·087
0·164 0·074 — 0·297 0·124 0·256 —
0·267 0·263 0·067 0·184 −0·017 0·168 0·223 0·264 0·078 — 0·248 0·201 0·070 0·206 0·068 0·086 0·141 0·299 0·015 0·759 — 0·232 0·163 4·39 1·82
0·374 0·422 4·65 1·49
0·196 0·294 4·61 1·77
0·284 0·362 3·30 1·02
0·114 0·221 2·85 1·15
0·179 0·263 3·08 1·01
0·181 0·226 2·97 1·12
0·195 0·109 2·26 1·06
0·301 0·189 2·91 1·09
0·409 0·213 3·19 1·97
0·349 0·175 3·01 1·12
— 0·745 — 2·30 2·27 0·98 1·00
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ξs are denoted by xs, observed variables measuring η by ys, coefficients relating ξs to η by γs, the matrix of factor loadings relating to xs to ξs by λx, and the matrix of factor loadings relating ys to η by λy. The questionnaire items corresponding to the observed variable names in Figure 1 are indicated in Table 1. Model fitting The above model was ¨ fitted to the ¨ data with the program LISREL 7 (Joreskog & Sorbom, 1988), using maximum likelihood estimation and with the correlation matrix relating the ys and xs as input. The scales of the latent variables were fixed by imposing values of unity for five elements of λx and one of the structural coefficients (γs) relating satisfaction to perception. Overall goodness of fit was evaluated in terms of both χ2 and Tanaka and Huba’s (1985) Goodness-of-Fit Index (GFI). TABLE 3. Estimates of the parameters of the measurement models Parameter Factor Loadings: λy (ε) Satisfaction Surroundings Building Relat. Satisfaction Factor Loadings: λx (δ) Evaluation Pleasantness Aesthetics Temperature Insulation Temperature Noise Noisiness Soundproofing Air Ventilation Air quality Space Spaciousness Distribution
Estimate
Standard error
0·475 (0·583) 0·597 (0·342) 0·568 (0·404)
0·104 (0·102) 0·113 (0·077) 0·111 (0·082)
1·000* (0·001) 0·655 (0·571)
0·000 (0·087) 0·101 (0·097)
1·000* (0·016) 0·509 (0·744)
0·000 (0·149) 0·122 (0·123)
1·000* (0·031) 0·769 (0·426)
0·000 (0·114) 0·113 (0·096)
1·000* (0·089) 0·830 (0·365)
0·000 (0·113) 0·112 (0·099)
1·000 (0·121) 0·307 (0·915)
0·000 (0·166) 0·120 (0·145)
Results Table 2 lists the means and standard deviations of all the observed variables, together with the Pearson product–moment correlation matrix used as input to the model-fitting program. Table 3 lists the estimated values of the elements of λx and λy (fixed values are marked with an asterisk), together with the measurement errors of the corresponding variables ε for ys, δ for xs) and the standard errors of both these estimates. The elements of λx and λy may be regarded as measures of the validity of the observed variable as a measure of the latent variable (Bollen, 1989); in this sense, the observed variable best measuring Satisfaction was Building (λy2= 0·597). The estimated standard errors in the λs (which of course depend on the scales of the observed and latent variables) are low, ranging from 0·101 (for Aesthetics) to 0·122 (for Temperature); so are the estimated standard errors of the measurement errors. The estimated parameters of the measurement models may therefore be deemed significant and reasonably well determined by the data. The adequacy of the five-factor model of environmental perception is corroborated by the matrix of estimated correlations among the ξs (Table 4): inter-ξ correlations (note the satisfactorily low standard errors) are considerably smaller than inter-x correlations, showing that perception is not overdetermined by the model. Table 5 lists the γs relating Satisfaction to the five environmental perception dimensions, together with the standard errors of these estimates; since it was assumed that the largest γ would be that relating Satisfaction to Evaluation, this was the coefficient fixed at unity for scaling purposes (see Methods). The perception variables other than Evaluation all have rather small γs, but two distinct groups are nevertheless distinguishable, one comprising Noise (γ=0·162) and Temperature (0·156), and the other Space (0·073) and Air (0·047). The coefficient of determination for the model was
TABLE 4. Correlations among user perception dimensions Estimate (Standard error)
1. 2. 3. 4. 5.
Evaluation Temperature Noise Air Space
1
2
3
4
5
— 0·337 (0·107) 0·306 (0·105) 0·219 (0·110) 0·439 (0·111)
— 0·199 (0·111) 0·180 (0·114) 0·198 (0·117)
— 0·449 (0·103) 0·238 (0·116)
— 0·335 (0·117)
—
Empirical Validation of a Model of User Satisfaction With Buildings
0·738. Both the goodness-of-fit measures were satisfactorily: χ2=79·48 (for 55 df.; p=0·017), GFI=0·885. There are several reasons for exercising caution in the use in the χ2 estimates. The chi-square approximation assumes that: (1) x has no kurtosis; (2) the covariance matrix is analysed; and (3) the sample is sufficiently large (Bollen, 1989). The Goodness of Fit Index (GFI), which is more robust and not affected by sample size, is close to 0·90 typically interpreted by researchers as indicating a good fit of the data (Kelloway, 1996).
Conclusions Of the three items conforming to the Satisfaction dimension, the greatest contribution was made by Building, i.e. by user Satisfaction with the building as a workplace. The LISREL analysis described above successfully parameterized our model of the dependence of satisfaction on the five dimensions of users’ perceptions of the building. In agreement with the findings of Weidemann and Anderson (1982), the factor best predicting user satisfaction was global Evaluation, which is hardly surprising if it is borne in mind that, like Evaluation, users’ satisfaction with their building is an attitude adopted by them toward their physical environment, and as such constitutes their overall judgement of their experience of this environment. Like POE studies (Becker, 1981; Vischer, 1989; Wineman, 1985), we found that user satisfaction also depended on users’ perceptions of the physical conditions of their building, although the influence of these factors was less marked than that of overall Evaluation. The most influential dimensions of user perception were Noise and Temperature, the least, Air and Space; but then, the relative importance of perceptions of different physical characteristics depends to a large extent on the building being studied. Farrenkopf and Roth (1980) have pointed out that variability on these dimensions depends on differences among users.
TABLE 5. Coefficients (γ) relating Satisfaction (η) with user perception dimensions (ξs) ξ Evaluation Temperature Noise Air Space
Estimate
S.E.
1·000* 0·156 0·162 0·047 0·073
0·000 0·134 0·141 0·132 0·148
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To sum up, our results show that subjective judgements of the environmental characteristics of a building provide an adequate characterization of that building in that they are useful for explaining user satisfaction with that building and its surroundings as a workplace. The predominance of the Evaluation dimension, both among the factors characterizing user perception and for explanation of user satisfaction, suggests that individuals are predisposed to evaluate their environments, that this is central to their environmental awareness, and hence that subjective assessment by users is a viable approach to the evaluation of buildings and a useful means of orienting building design. The post-occupancy evaluation is a good example of a intervention that began with programming and ended with evaluation of design changes. Knowing the features users and their needs will be produce more habitable structures. User provide information to a designer who then creates the design. Like Marans and Spreckelmeyer (1982) we think that a POE should focus not only on the physical conditions of a building, but also on its overall architectural quality or aesthetics.
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