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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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