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Table 1 The difference in hand hygiene compliance in 3047 pairs of overtly and covertly observed hand hygiene opportunities stratified by department, occupation, observation time, and location

From: Identifying heterogeneity in the Hawthorne effect on hand hygiene observation: a cohort study of overtly and covertly observed results

Overt observation

Number of matched pairs (%)

Covert observation

Matched odds ratio

p valuea

Hand rubbing/washing

No hand rubbing/washing

Department

ā€ƒMedicine (Nā€‰=ā€‰1212)

Ā Ā 

3.0

<ā€‰0.001

ā€ƒā€ƒHand rubbing/washing

510 (42.1)

418 (34.5)

Ā Ā 

ā€ƒā€ƒNo hand rubbing/washing

139 (11.5)

145 (12.0)

Ā Ā 

ā€ƒSurgery (Nā€‰=ā€‰1258)

Ā Ā 

3.6

<ā€‰0.001

ā€ƒā€ƒHand rubbing/washing

475 (37.8)

482 (38.3)

Ā Ā 

ā€ƒā€ƒNo hand rubbing/washing

135 (10.7)

166 (13.2)

Ā Ā 

ā€ƒPaediatrics (Nā€‰=ā€‰463)

Ā Ā 

2.7

<ā€‰0.001

ā€ƒā€ƒHand rubbing/washing

292 (63.1)

112 (24.2)

Ā Ā 

ā€ƒā€ƒNo hand rubbing/washing

41 (8.9)

18 (3.9)

Ā Ā 

ā€ƒGynaecology/obstetrics (Nā€‰=ā€‰114)

Ā Ā 

2.9

0.001

ā€ƒā€ƒHand rubbing/washing

60 (52.6)

35 (30.7)

Ā Ā 

ā€ƒā€ƒNo hand rubbing/washing

12 (10.5)

7 (6.1)

Ā Ā 

Occupation

ā€ƒNurse (Nā€‰=ā€‰2105)

Ā Ā 

5.3

<ā€‰0.001

ā€ƒā€ƒHand rubbing/washing

994 (47.2)

778 (37.0)

Ā Ā 

ā€ƒā€ƒNo hand rubbing/washing

146 (6.9)

187 (8.9)

Ā Ā 

ā€ƒPhysician (Nā€‰=ā€‰619)

Ā Ā 

1.6

<ā€‰0.001

ā€ƒā€ƒHand rubbing/washing

241 (38.9)

179 (28.9)

Ā Ā 

ā€ƒā€ƒNo hand rubbing/washing

114 (18.4)

85 (13.7)

Ā Ā 

ā€ƒCaregiver (Nā€‰=ā€‰106)

Ā Ā 

1.4

0.302

ā€ƒā€ƒHand rubbing/washing

26 (24.5)

27 (25.5)

Ā Ā 

ā€ƒā€ƒNo hand rubbing/washing

19 (17.9)

34 (32.1)

Ā Ā 

ā€ƒOthers (Nā€‰=ā€‰217)

Ā Ā 

1.3

0.184

ā€ƒā€ƒHand rubbing/washing

76 (35.0)

63 (29.0)

Ā Ā 

ā€ƒā€ƒNo hand rubbing/washing

48 (22.1)

30 (13.8)

Ā Ā 

Timeb

ā€ƒDay shift (Nā€‰=ā€‰2493)

Ā Ā 

3.1

<ā€‰0.001

ā€ƒā€ƒHand rubbing/washing

1120 (44.9)

838 (33.6)

Ā Ā 

ā€ƒā€ƒNo hand rubbing/washing

273 (11.0)

262 (10.5)

Ā Ā 

ā€ƒEarly night shift (Nā€‰=ā€‰516)

Ā Ā 

3.7

<ā€‰0.001

ā€ƒā€ƒHand rubbing/washing

208 (40.3)

190 (36.8)

Ā Ā 

ā€ƒā€ƒNo hand rubbing/washing

52 (10.1)

66 (12.8)

Ā Ā 

ā€ƒLate night shift (Nā€‰=ā€‰38)

Ā Ā 

9.5

<ā€‰0.001

ā€ƒā€ƒHand rubbing/washing

9 (23.7)

19 (50.0)

Ā Ā 

ā€ƒā€ƒNo hand rubbing/washing

2 (5.3)

8 (21.1)

Ā Ā 

Location

ā€ƒWard (Nā€‰=ā€‰2034)

Ā Ā 

3.7

<ā€‰0.001

ā€ƒā€ƒHand rubbing/washing

815 (40.1)

774 (38.1)

Ā Ā 

ā€ƒā€ƒNo hand rubbing/washing

208 (10.2)

237 (11.7)

Ā Ā 

ā€ƒIntensive care unit (Nā€‰=ā€‰880)

Ā Ā 

1.9

<ā€‰0.001

ā€ƒā€ƒHand rubbing/washing

498 (56.6)

211 (24.0)

Ā Ā 

ā€ƒā€ƒNo hand rubbing/washing

111 (12.6)

60 (6.8)

Ā Ā 

ā€ƒOutpatient department (Nā€‰=ā€‰133)

Ā Ā 

7.8

<ā€‰0.001

ā€ƒā€ƒHand rubbing/washing

24 (18.0)

62 (46.6)

Ā Ā 

ā€ƒā€ƒNo hand rubbing/washing

8 (6.0)

39 (29.3)

Ā Ā 

Number of indications per hand hygiene opportunity

ā€ƒ1 (Nā€‰=ā€‰2301)

Ā Ā 

3.1

<ā€‰0.001

ā€ƒā€ƒHand rubbing/washing

963 (41.9)

801 (34.8)

Ā Ā 

ā€ƒā€ƒNo hand rubbing/washing

260 (11.3)

277 (12.0)

Ā Ā 

ā€ƒ2 (Nā€‰=ā€‰42)

Ā Ā 

2.7

0.227

ā€ƒā€ƒHand rubbing/washing

28 (66.7)

8 (19.0)

Ā Ā 

ā€ƒā€ƒNo hand rubbing/washing

3 (7.1)

3 (7.1)

Ā Ā 

Hand hygiene indication

ā€ƒBefore touching a patient (Nā€‰=ā€‰270)

Ā Ā 

3.1

<ā€‰0.001

ā€ƒā€ƒHand rubbing/washing

96 (35.6)

99 (36.7)

Ā Ā 

ā€ƒā€ƒNo hand rubbing/washing

32 (11.9)

43 (15.9)

Ā Ā 

ā€ƒBefore clean/aseptic procedures (Nā€‰=ā€‰19)

Ā Ā Ā 

0.063

ā€ƒā€ƒHand rubbing/washing

10 (52.6)

5 (26.3)

Ā Ā 

ā€ƒā€ƒNo hand rubbing/washing

0 (0)

4 (21.1)

Ā Ā 

ā€ƒAfter body fluid exposure risk (Nā€‰=ā€‰18)

Ā Ā 

6.0

0.125

ā€ƒā€ƒHand rubbing/washing

8 (44.4)

6 (33.3)

Ā Ā 

ā€ƒā€ƒNo hand rubbing/washing

1 (5.6)

3 (16.7)

Ā Ā 

ā€ƒAfter touching a patient (Nā€‰=ā€‰287)

Ā Ā 

3.1

<ā€‰0.001

ā€ƒā€ƒHand rubbing/washing

140 (48.8)

99 (34.5)

Ā Ā 

ā€ƒā€ƒNo hand rubbing/washing

32 (11.1)

16 (5.6)

Ā Ā 

ā€ƒAfter touching patient surroundings (Nā€‰=ā€‰56)

Ā Ā 

1.1

1.000

ā€ƒā€ƒHand rubbing/washing

16 (28.6)

15 (26.8)

Ā Ā 

ā€ƒā€ƒNo hand rubbing/washing

14 (25.0)

11 (19.6)

Ā Ā 

Overall (Nā€‰=ā€‰3047)

Ā Ā 

3.2

<ā€‰0.001

ā€ƒā€ƒHand rubbing/washing

1337 (43.9)

1047 (34.4)

Ā Ā 

ā€ƒā€ƒNo hand rubbing/washing

327 (10.7)

336 (11.0)

Ā Ā 
  1. aMcNemarā€™s tests were used to analyse the differences between overtly and covertly observed hand hygiene compliance in each category
  2. bDay shift, 0800ā€“1600Ā h; early night shift, 1600ā€“2400Ā h; late night shift, 2400ā€“0800Ā h