Results

Using the overall comfort questionnaire data from the 10 participating countries, the mean values and the distribution of the values for the four versions of the combined comfort index did not differ greatly (Table 12).

TABLE 12 Mean values and distribution of values of the four CCIs

 

Mean

Standard
deviation

Median

Min.

Max.

10th
percentile

25th
percentile

75th
percentile

90th
percentile

CCI-1

3.64

0.64

3.75

1.0

5.0

2.75

3.25

4.0

4.5

CCI-2

3.73

0.62

3.8

1.0

5.0

2.9

3.4

4.1

4.4

CCI-3

2.64

0.77

2.5

1.0

6.0

1.75

2.0

3.25

3.75

CCI-4

2.57

0.79

2.5

1.0

6.0

1.7

2.0

3.0

3.7

To test the performance (informative value) of the CCIs we compared the CCI values with children’s responses to the question “Do you like your classroom?” (B1).

Table 13 shows the significant correlation coefficients found using Spearman’s correlations between the scores for question BI and the CCIs.

TABLE 13 Spearman’s correlation between scores for B1 and the CCIs

Correlation coefficient with B1 scores

 

CCI-1

0.1242

CCI-2

0.2693

CCI-3

-0.1128

CCI-4

-0.2540

According to the results of the regression analysis, all CCIs were significantly associated with the scores for this question (even if with a low adjusted R2) (Table 14).

TABLE 14 Association of CCIs with question B1

 

Coefficient

Standard error

adjR2

P>(t)

95% conf. intervals

CCI-1

0.39416

0.02696

0.0312

0.0000

0.34131    0.44702

CCI-2

0.68242

0.02599

0.0945

0.0000

0.63147    0.73336

CCI-3

-0.28879

0.02031

0.0296

0.0000

-0.32861   -0.24899

CCI-4

-0.50733

0.01967

0.0915

0.0000

-0.54589   -0.46876

The following two conclusions can be drawn:

  • The weighted indexes performed better than the unweighted ones.
  • The original scoring system (CCI-1 and CCI-2) was better than the scoring weighted for extreme perceptions.

At the meeting of Italian and Hungarian experts held in Budapest on March 4, 2013, it was decided that extreme values give an unclear picture, thus only CCI-1 and CCI-2 were considered in the following procedures.

The following observations were also made:

  • Statistical analysis showed that both CCI-1 and CCI-2 scores were significantly different according to gender and age.
  • There was significant heterogeneity between CCI-1 and CCI-2 among countries.
  • Both CCI-1 and CCI-2 were significantly associated with headaches among children (Question B7b). There was not much difference in the correlation coefficients between the two CCIs (CCI-1: -0.1245; CCI-2: -0.1353)
  • Spearman’s correlation analysis between CCIs and the measured values for temperature, relative humidity and CO2 concentrations are shown in Table 15. Coefficients were highest for (and statistically significant only in the case of) relative humidity.
TABLE 15 Spearman’s correlation between CCIs and measured values

 

Temperature (°C)

Relative humidity (%)

CO2 (ppm)

CCI-1

0.0314

-0.0908***

0.0337

CCI-2

0.0063

-0.1346***

0.0073

*** p<0.001

 
Ministero Dell'ambiente Italian Trust Fund