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Table 2 Call outcome information and rates for by sample frame and overall (combined)

From: Inclusion of mobile phone numbers into an ongoing population health survey in New South Wales, Australia: design, methods, call outcomes, costs and sample representativeness

 

Landline frame

Mobile frame

Overall

T=Total phone numbers used

21350

17534

38884

I=Complete Interviews (1.1)

2171

1224

3395

Adults

1865

1085

2950

Children

306

139

445

P=Partial

0

0

0

R=Refusal and break off (2.1)

868

457

1325

NC=Non Contact (2.2)

660

238

898

O=Other (2.0, 2.3)

1163

767

1930

e: estimated proportion of cases of unknown eligibility that are eligible.

0.29

0.22

0.25

UH=Unknown Household (3.1)

4553

5450

10003

UO=Unknown other (3.2-3.9)

0

0

0

NE=Not eligible

11935

9462

21397

 Fax data line (NE F )

1352

33

1385

 Non-working number or unusual tone (NE NW )

2390

2637

5027

 Business, government office, or other organizations(NE B )

8100

826

8926

 Not in NSW or mobile owned by child (mobile frame)(NE I )

93

5966

6059

Survey length, collection costs and productivity

   

Average survey length (mins)

17.2

15.6

 

Average call costs (per completed interview)

$7.45

$38.90

 

Average interviewer time costs (per completed interview)

$23.68

$35.53

 

Total average costs (call costs plus interviewer time costs)

$31.13

$74.42

 

Telephone numbers used to get a contact: T/(I+R+NEI+NEB)

1.9

2.1

 

Telephone numbers used to get an eligible contact: T/(I+R)

7.0

10.5

 

Telephone numbers used to get a completed interview: T/I

9.8

14.4

 

Response Rates

   

Response Rate 1: I/(I+P) + (R+NC+O) + (UH+UO)

23.1%

15.0%

18.6%

Response Rate 2: (I+P)/(I+P) + (R+NC+O) + (UH+UO)

23.1%

15.0%

18.6%

Response Rate 3: I/((I+P) + (R+NC+O) + e(UH+UO) )

35.1%

31.5%

33.1%

Response Rate 4: (I+P)/((I+P) + (R+NC+O) + e(UH+UO) )

35.1%

31.5%

33.1%

Cooperation Rates

   

Cooperation Rate 1: I/(I+P)+R+O)

51.7%

50.0%

50.7%

Cooperation Rate 2: (I+P)/((I+P)+R+O))

51.7%

50.0%

50.7%

Cooperation Rate 3: I/((I+P)+R))

71.4%

72.8%

72.2%

Cooperation Rate 4: (I+P)/((I+P)+R))

71.4%

72.8%

72.2%

Refusal Rates

   

Refusal Rate 1: R/((I+P)+(R+NC+O) + UH + UO))

9.2%

5.6%

7.2%

Refusal Rate 2: R/((I+P)+(R+NC+O) + e(UH + UO))

14.0%

11.7%

12.8%

Refusal Rate 3: R/((I+P)+(R+NC+O))

17.9%

17.0%

17.4%

Contact Rates

   

Contact Rate 1: (I+P)+R+O / (I+P)+R+O+NC+ (UH + UO)

44.6%

30.1%

36.5%

Contact Rate 2: (I+P)+R+O / (I+P)+R+O+NC + e(UH+UO)

68.0%

62.9%

65.1%

Contact Rate 3: (I+P)+R+O / (I+P)+R+O+NC

86.4%

91.1%

89.1%

  1. Notes to Table 2: AAPOR Categories [28] are as follows: Interview (I) = Complete interviews (1.1); Refusal (R) = Respondent refusal (2.112), Household refusal and break off (2.1); Non-contact (NC) = Respondent never available(2.2), away for duration of survey (2.21); Other (O) = Respondent physically or mentally unable to complete interview (2.32), Non-translated language(2.333), Other non-refusal : hang up said nothing/ terminated by interviewer/technical problems (2.3); Unknown Household (UH) = Engaged busy (3.12), No answer (3.13), always answering machine (3.14); Not eligible (NE) = Fax data line (4.2), Non-working number (4.3), unusual tone (4.31), Business, government office, other organizations (4.51), Non-eligible respondent: not in NSW/mobile owned/answered by child (4.7);
  2. Calculation of each rate for Overall = (RA* (Na+λNab A))+ (RB * (Nb+(1-λ)Nab B)) where R frame rate; N population proportion; λ=overlap adjustment (set 0.5); A landline sample frame; B denotes mobile sample frame; a landline-only phone users; b mobile-only phone users; ab denotes both mobile phone and landline users.
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BMC Medical Research Methodology

ISSN: 1471-2288

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