Skip to main content

Table 1 Smokefree signage and dog control signage at 63 children’s playgrounds in 21 contiguous local government authority areas in the lower North Island of New Zealand (for signs within 10 m of the playground equipment)

From: Smokefree signage at children’s playgrounds: Field observations and comparison with Google Street View

Characteristic

Smokefree signs [95% CI]

Dog control signs [95% CI]

P-value for difference

Playgrounds with any sign (N)

28

20

% of all playgrounds with any sign

44% (28/63)

32% (20/63)

0.149

Local government areas with any signs (n = 21 areas)

71%

48%

0.133

Playgrounds in city areas (n = 39) with signs

49%

36%

0.264

Playgrounds in other local government areas (n = 24)

38%

25%

0.373

Total signs (ie, multiple signs in some playgrounds)

50

28

Mean number of signs per playground (SD)

0.79 (1.23)

0.44 (0.80)

0.095

Range for signs per playground (N)

0 to 6

0 to 4

Sign size

 Average in cm2 (SD)

1057 (960)

1154 (1161)

0.749

 Median in cm2

600

768

 Inter-quartile range (cm2)

233 to 1800

440 to 1350

 Full range (cm2)

42 to 2880

100 to 3600

Performance of GSV (using field observations as the gold standard)

 Play equipment not visible on GSV (too far from a road) – these results excluded from further analysis

11 (17.5%)

11 (17.5%)

 True positives [A]

4

7

 True negatives [B]

26

32

 False positives [C]a

1

3

 False negatives [D]

21

10

 Sensitivity [A/(A + D)]

16% [5% – 34%]

41% [20% – 65%]

0.087

 Specificity [B/(B + C)]

96% [83% – 100%]

91% [78% – 98%]

0.505

 Positive predictive value [A/(A + C)]

80% [33% – 99%]

70% [38% – 92%]

0.747

 Negative predictive value [B/(B + D)]

55% [41% – 69%]

76% [62% – 87%]

0.043

  1. a These “false positives” may be a true error (the GSV user mis-interpreting another sign eg, a “no horses” sign for a “no dogs” sign) or may actually reflect a smokefree or dog control sign that was previously present when the GSV image was taken several years ago, but was not present in the field observations in 2016