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Results of the Discrete Trend Method The CV of every item was > 0.2, indicating good sensitivity among the items. Therefore, all the items were retained.
Results of the Critical Ratio Method At the level of α = 0.05, there were no statistically significant differences in the average scores of items “Access to public toilets” (Can you find public toilets nearby at an outdoor location?) and “Measures to promote a healthy diet ” (Can you obtain knowledge about healthy diets at your residence?) between the high-score group and the low-score one.
Results of the Correlation Coefficient Method As the score of each item is a graded variable that cannot be directly calculated by the linear correlation coefficient, it was judged using Spearman’s rank correlation coefficient. Through this method, items “City functional lighting” (Does the night time lighting in the area of residence satisfy the demands of night time travel?) and “Daily disposal of the community’s garbage” (Is the garbage in the area of residence cleared on time and without being left overnight?) were not within the standard limit.
Results of Exploratory Factor Analysis We conducted the Kaiser-Meyer-Olkin (KMO) and Bartlett tests. The KMO value was close to 1 (KMO value = 0.903). Meanwhile, P < 0.01 was detected in the Bartlett test of sphericity, and the null hypothesis was rejected, implying that there were correlations among the variables. All these results indicated that the data were applicable for factor analysis. The results showed that five common factors (characteristic root > 1) were produced, and the loading for none of the items of the five common factors was under 0.4, so no indicator was deleted.
Based on these results, none of the items met two criteria for deletion at the same time. Hence, all 22 items were retained.
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Since all 22 items were retained, the five common factors resulting from the analysis described above were taken as the dimensions of the scale to construct the scale’s structure. The five common factors represented specific meanings combined with professional knowledge. Factor 1 stood for evaluation of urban lifestyle, including eight items (garbage collection, smoking control and bans in public places, vaccination availability, voluntary blood donations, measures to promote a healthy diet, measures to promote personal hygiene, vector control, and services from community health service centers). There were five items related to Factor 2 regarding the evaluation of various aspects of urban governance, including air quality, drinking-water safety, food safety, management of fair-trade markets, and management of street vendors. Factor 3 represented the evaluation of urban basic functions, including three items: urban public fitness facilities, urban greening, and healthy places. Factor 4 for the evaluation of the urban environment included four items, including garbage-collection facilities, “No Smoking” signs, daily disposal of the community’s garbage, and urban sanitation. There were two items for Factor 5 that pertained to urban amenities, and these included City functional lighting and access to public toilets (Table 1).
Item Loading Urban lifestyle Urban governance Urban basic functions Urban environmental sanitation Urban amenities Garbage collection 0.621 Smoking control 0.700 Vaccinations 0.734 Voluntary blood donations 0.707 Measures to promote a healthy diet 0.756 Measures to promote personal hygiene 0.686 Vector control 0.710 Services from community health service centers 0.596 Air quality 0.504 Drinking-water safety 0.616 Food safety 0.705 Management of fair-trade markets 0.705 Management of street vendors 0.616 Urban public fitness facilities 0.751 Urban greening 0.715 Healthy places 0.582 Garbage-collection facilities 0.607 “No Smoking” signs 0.498 Daily disposal of the community’s garbage 0.550 Urban sanitation 0.464 City functional lighting 0.763 Access to public toilets 0.626 Characteristic root 6.318 1.794 1.433 1.007 1.027 Contribution rate (%) 28.717 8.153 6.514 4.894 4.667 Cumulative contribution rate (%) 28.717 36.870 43.384 48.278 52.945 Table 1. Results of the exploratory factor analysis
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Reliability Evaluation Evaluations of internal consistency reflect the consistency and stability of a scale’s items. In this study, the total scale and all the factors were subjected to Cronbach’s α coefficient analysis. We found the total Cronbach’s α coefficient of the scale for subjective perceptions of the built environments of hygienic cities in China to be 0.876 (> 0.6), suggesting that the scale has an adequate level of internal consistency. Furthermore, the Cronbach’s α coefficient of the five dimensions was 0.879 (urban lifestyle), 0.706 (urban governance), 0.593 (urban basic functions), 0.533 (urban environmental sanitation), and 0.402 (urban amenities). According to the literature, the Cronbach’s α coefficient of a scale containing fewer than four items may be below 0.6 or 0.5[11]. This indicates that the internal consistency of urban environmental sanitation (four items) and urban amenities (two items) is acceptable.
In addition, the items of the scale were split into two equivalent parts, and the correlation coefficient between the scores of the two parts was calculated using the Spearman-Brown formula. The split-half reliability coefficient of the scale was 0.796.
Construct Validity Evaluation A significance test of factor loading, the model’s goodness-of-fit test, and an analysis of the correlations among the dimensions were used to evaluate the construct validity.
(1) Significance test of factor loading
The differences in all parameters were statistically significant (P < 0.01), suggesting that the measurement model confirmed our hypothesis. None of the items had a factor loading lower than 0.32, implying that the latent variables adequately explained the items and that the theoretical model was accurate (Table 2).
Item Dimension Unstd. S.E. Z P Std. Garbage collection Urban lifestyle 1.000 0.677 Smoking control Urban lifestyle 1.044 0.072 14.561 < 0.01 0.699 Vaccinations Urban lifestyle 1.025 0.069 14.774 < 0.01 0.710 Voluntary blood donations Urban lifestyle 0.960 0.067 14.406 < 0.01 0.690 Measures promoting a healthy diet Urban lifestyle 1.103 0.073 15.205 < 0.01 0.734 Measures promoting personal hygiene Urban lifestyle 0.970 0.066 14.738 < 0.01 0.708 Vector control Urban lifestyle 1.043 0.071 14.606 < 0.01 0.701 Services from community health service centers Urban lifestyle 0.904 0.070 12.879 < 0.01 0.610 Air quality Urban governance 1.000 0.502 Drinking-water safety Urban governance 1.076 0.120 8.967 < 0.01 0.583 Food safety Urban governance 1.061 0.114 9.280 < 0.01 0.624 Management of fair-trade markets Urban governance 1.075 0.116 9.271 < 0.01 0.623 Management of street vendors Urban governance 1.114 0.131 8.533 < 0.01 0.534 Urban public fitness facilities Urban basic functions 1.000 0.622 Urban greening Urban basic functions 0.793 0.102 7.801 < 0.01 0.495 Health places Urban basic functions 0.974 0.115 8.492 < 0.01 0.594 Garbage collection facilities Urban environmental sanitation 1.000 0.343 ‘No Smoking’ signs Urban environmental sanitation 0.768 0.131 5.852 < 0.01 0.437 Daily disposal of the community’s garbage Urban environmental sanitation 0.868 0.144 6.023 < 0.01 0.469 Urban sanitation Urban environmental sanitation 1.209 0.180 6.728 < 0.01 0.690 City functional lighting Urban amenities 1.000 0.457 Access to public toilets Urban amenities 1.275 0.203 6.295 < 0.01 0.550 Note. Unstd., Unstandard Estimates of factor loadings; S.E., Standard Error of Mean; Std., Standard Estimates of factor loadings. Table 2. Estimations of factor loadings
(2) The model’s goodness-of-fit test
The results of the goodness-of-fit test for our model displayed χ2/df = 2.46 < 3 (critical value), RMSEA = 0.052 < 0.08 (critical value), AGFI = 0.902 > 0.9 (critical value), GFI > 0.9 (critical value), IFI > 0.9 (critical value), CFI > 0.9 (critical value), PNFI > 0.5 (critical value), and PCFI > 0.5 (critical value). This indicates that our model possesses adequate fitness (Table 3).
Index χ2/df AGFI RMSEA GFI IFI CFI PNFI PCFI Result 2.46 0.902 0.052 0.923 0.913 0.912 0.734 0.786 Evaluation criteria < 3 > 0.9 < 0.08 > 0.9 > 0.9 > 0.9 > 0.5 > 0.5 Note. χ2/df: Chi-square/degrees of freedom; AGFI: Adjusted goodness-of-fit index; RMSEA: Root mean square error of approximation; GFI: Goodness-of-fit index; IFI: Incremental fit index; CFI: Comparative fit index; PNFI: Parsimony-adjusted normed fit index; PCFI: Parsimony comparative fit index. Table 3. Model fitness results of confirmatory factor analysis
(3) Analysis of correlations among dimensions
The Pearson correlation coefficients between the dimensions and the total scale for subjective perceptions of the built environments of China’s hygienic cities had statistical significance. Specifically, the correlation coefficient between urban amenities and the total scale was 0.454, while the correlation coefficients of the remaining dimensions with the total scale were > 0.60. The correlation coefficients between each dimension and others were all smaller than the correlation coefficients between the dimension and the total scale, indicating that the dimension’s structure demonstrated discriminant validity. Furthermore, the Cronbach’s α coefficient of each dimension was greater than the correlation coefficients between the dimension under examination and the others, suggesting a favorable convergent validity of the dimension’s structure (Table 4).
Dimension Total
scoreUrban
lifestyle V1Urban
governance V2Urban basic
functions V3Urban
environment V4Urban
amenities V5Total scale 1 Urban lifestyle V1 0.864** 1 Urban governance V2 0.678** 0.478** 1 Urban basic functions V3 0.678** 0.393** 0.273** 1 Urban environmental sanitation V4 0.709** 0.513** 0.418* 0.364** 1 Urban amenities V5 0.454** 0.292** 0.341** 0.214** 0.271** 1 Note. **α = 0.01 (two-tailed), significant correlation. Table 4. Correlation coefficients among dimensions
Developing a Subjective Evaluation Scale for Assessing the Built Environments of China’s Hygienic City Initiative
doi: 10.3967/bes2021.049
- Received Date: 2020-07-02
- Accepted Date: 2020-11-30
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Key words:
- Subjective built environment /
- China’s Hygienic City /
- Reliability and validity /
- Scale
Abstract:
Citation: | ZHENG Wen Jing, YAO Hong Yan, LIU Jian Jun, YU Shi Cheng. Developing a Subjective Evaluation Scale for Assessing the Built Environments of China’s Hygienic City Initiative[J]. Biomedical and Environmental Sciences, 2021, 34(5): 372-378. doi: 10.3967/bes2021.049 |