Uptake of mobile phone surveys (MPS) is increasing in many low- and middle-income countries, particularly within the context of data collection on non-communicable diseases (NCDs) behavioural risk factors. One barrier to collecting representative data through MPS is capturing data from older participants.Respondent driven sampling (RDS) consists of chain-referral strategies where existing study subjects recruit follow-up participants purposively based on predefined eligibility criteria. Adapting RDS strategies to MPS efforts could, theoretically, yield higher rates of participation for that age group.
To investigate factors that influence the perceived acceptability of a RDS recruitment method for MPS involving people over 45 years of age living in Colombia.
An MPS recruitment strategy deploying RDS techniques was piloted to increase participation of older populations. We conducted a qualitative study that drew from surveys with open and closed-ended items, semi-structured interviews for feedback, and focus group discussions to explore perceptions of the strategy and barriers to its application amongst MPS participants.
The strategy\'s success is affected by factors such as cultural adaptation, institutional credibility and public trust, data protection, and challenges with mobile phone technology. These factors are relevant to individuals\' willingness to facilitate RDS efforts targeting hard-to-reach people. Recruitment strategies are valuable in part because hard-to-reach populations are often most accessible through their contacts within their social network who can serve as trust liaisons and drive engagement.
These findings may inform future studies where similar interventions are being considered to improve access to mobile phone-based data collection amongst hard-to-reach groups.

Random digit dial surveys with mobile phones risk under-representation of women. To address this, we compare the characteristics of women recruited directly with those of women recruited through referrals from male household members. The referral process improves representation of vulnerable groups, such as young women, the asset poor, and those living in areas with low connectivity. Among mobile phone users, we show a referral (rather than a direct dial) protocol includes more nationally representative proportions of women with these attributes. While seeking intra-household referrals may improve representation, we show that it does so at a higher cost.

This is the first study to examine the costs of conducting a mobile phone survey (MPS) through interactive voice response (IVR) to collect information on risk factors for noncommunicable diseases (NCD) in three low- and middle-income countries (LMIC); Bangladesh, Colombia, and Uganda.
This is a micro-costing study conducted from the perspective of the payer/funder with a 1-year horizon. The study evaluates the fixed costs and variable costs of implementing one nationally representative MPS for NCD risk factors of the adult population. In this costing study, we estimated the sample size of calls required to achieve a population-representative survey and associated incentives. Cost inputs were obtained from direct economic costs incurred by a central study team, from country-specific collaborators, and from platform developers who participated in the deployment of these MPS during 2017. Costs were reported in US dollars (USD). A sensitivity analysis was conducted assessing different scenarios of pricing and incentive strategies. Also, costs were calculated for a survey deployed targeting only adults younger than 45 years.
We estimated the fixed costs ranging between $47,000 USD and $74,000 USD. Variable costs were found to be between $32,000 USD and $129,000 USD per nationally representative survey. The main cost driver was the number of calls required to meet the sample size, and its variability largely depends on the extent of mobile phone coverage and access in the country. Therefore, a larger number of calls were estimated to survey specific harder-to-reach sub-populations.
Mobile phone surveys have the potential to be a relatively less expensive and timely method of collecting survey information than face-to-face surveys, allowing decision-makers to deploy survey-based monitoring or evaluation programs more frequently than it would be possible having only face-to-face contact. The main driver of variable costs is survey time, and most of the variability across countries is attributable to the sampling differences associated to reaching out to population subgroups with low mobile phone ownership or access.

Data collection on noncommunicable disease (NCD) behavioral risk factors has traditionally been carried out through face-to-face surveys. However, its high costs and logistical difficulties can lead to lack of timely statistics for planning, particularly in low and middle-income countries. Mobile phone surveys (MPS) have the potential to fill these gaps.
This study explores perceptions, feasibility and strategies to increase the acceptability and response rate of health surveys administered through MPS using interactive voice response in Colombia.
A sequential multimodal exploratory design was used. We conducted key informant interviews (KII) with stakeholders from government and academia; focus group discussions (FGDs) and user-group tests (UGTs) with young adults and elderly people living in rural and urban settings (men and women). The KII and FGDs explored perceptions of using mobile phones for NCD surveys. In the UGTs, participants were administered an IVR survey, and they provided feedback on its usability and potential improvement.
Between February and November 2017, we conducted 7 KII, 6 FGDs (n = 54) and 4 UGTs (n = 34). Most participants consider MPS is a novel way to explore risk factors in NCDs. They also recognize challenges for their implementation including security issues, technological literacy and telecommunications coverage, especially in rural areas. It was recommended to promote the survey using mass media before its deployment and stressing its objectives, responsible institution and data privacy safeguards. The preferences in the survey administration relate to factors such as skills in the use of mobile phones, age, availability of time and educational level. The participants recommend questionnaires shorter than 10 minutes.
The possibility of obtaining data through MPS at a population level represents an opportunity to improve the availability of risk-factor data. Steps towards increasing the acceptability and overcoming technological and methodological challenges need to be taken.

UNASSIGNED: Decision-makers need up to date information on risk factors for effective prevention and control of non-communicable diseases (NCDs). Currently available surveys are infrequent and costly to implement. The objective of the study was to explore perceptions on using an interactive voice response (IVR) survey for data collection on NCD risk factors.
UNASSIGNED: Five focus group discussions (FGDs), including rural and urban, elderly and young adults, male and female groups; and eleven key informant interviews (KIIs) of researchers and NCD policy makers were conducted. Respondents were audio recorded and data were transcribed into text. Data were entered into QDA miner software for analysis. Meaningful units were generated and then merged into codes and categories. Quotes are presented highlighting findings.
UNASSIGNED: At the individual level, age, gender, disability, past experience and being technology literate were perceived as key determinants on whether respondents would accept an IVR survey. Receiving the IVR at a time at which people are usually available to take calls increases participation. However, technological accessibility like presence of a mobile network signal and possession of mobile phones were critical for use of IVR. Participants recommended that community sensitization activities be provided, IVR be conducted at appropriate times and frequency, and that incentives may improve survey participation.
UNASSIGNED: IVR has the potential to quickly collect data from a wide geographic scope. However, caution needs to be taken to ensure that certain categories of people are not excluded because of their location, ability, age or gender. Sensitization prior to the survey, proper timing and structured incentives could increase participation.

UNASSIGNED: The global proliferation of mobile phones offers opportunity for improved non-communicable disease (NCD) data collection by interviewing participants using interactive voice response (IVR) surveys. We assessed whether airtime incentives can improve cooperation and response rates for an NCD IVR survey in Bangladesh and Uganda.
UNASSIGNED: Participants were randomised to three arms: a) no incentive, b) 1X incentive or c) 2X incentive, where X was set to airtime of 50 Bangladesh Taka (US$0.60) and 5000 Ugandan Shillings (UGX; US$1.35). Adults aged 18 years and older who had a working mobile phone were sampled using random digit dialling. The primary outcomes, cooperation and response rates as defined by the American Association of Public Opinion Research, were analysed using log-binomial regression model.
UNASSIGNED: Between 14 June and 14 July 2017, 440 262 phone calls were made in Bangladesh. The cooperation and response rates were, respectively, 28.8% (353/1227) and 19.2% (580/3016) in control, 39.2% (370/945) and 23.9% (507/2120) in 50 Taka and 40.0% (362/906) and 24.8% (532/2148) in 100 Taka incentive groups. Cooperation and response rates, respectively, were significantly higher in both the 50 Taka (risk ratio (RR) 1.36, 95% CI 1.21 to 1.53) and (RR 1.24, 95% CI 1.12 to 1.38), and 100 Taka groups (RR 1.39, 95% CI 1.23 to 1.56) and (RR 1.29, 95% CI 1.16 to 1.43), as compared with the controls. In Uganda, 174 157 phone calls were made from 26 March to 22 April 2017. The cooperation and response rates were, respectively, 44.7% (377/844) and 35.2% (552/1570) in control, 57.6% (404/701) and 39.3% (508/1293) in 5000 UGX and 58.8% (421/716) and 40.3% (535/1328) in 10 000 UGX groups. Cooperation and response rates were significantly higher, respectively in the 5000 UGX (RR 1.29, 95% CI 1.17 to 1.42) and (RR 1.12, 95% CI 1.02 to 1.23), and 10 000 UGX groups (RR 1.32, 95% CI 1.19 to 1.45) and (RR 1.15, 95% CI 1.04 to 1.26), as compared with the control group.
UNASSIGNED: In two diverse settings, the provision of an airtime incentive significantly improved both the cooperation and response rates of an IVR survey, with no significant difference between the two incentive amounts.
UNASSIGNED: NCT03768323.

National and subnational level surveys are important for monitoring disease burden, prioritizing resource allocation, and evaluating public health policies. As mobile phone access and ownership become more common globally, mobile phone surveys (MPSs) offer an opportunity to supplement traditional public health household surveys.
The objective of this study was to systematically review the current landscape of MPSs to collect population-level estimates in low- and middle-income countries (LMICs).
Primary and gray literature from 7 online databases were systematically searched for studies that deployed MPSs to collect population-level estimates. Titles and abstracts were screened on primary inclusion and exclusion criteria by two research assistants. Articles that met primary screening requirements were read in full and screened for secondary eligibility criteria. Articles included in review were grouped into the following three categories by their survey modality: (1) interactive voice response (IVR), (2) short message service (SMS), and (3) human operator or computer-assisted telephone interviews (CATI). Data were abstracted by two research assistants. The conduct and reporting of the review conformed to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement.
A total of 6625 articles were identified through the literature review. Overall, 11 articles were identified that contained 19 MPS (CATI, IVR, or SMS) surveys to collect population-level estimates across a range of topics. MPSs were used in Latin America (n=8), the Middle East (n=1), South Asia (n=2), and sub-Saharan Africa (n=8). Nine articles presented results for 10 CATI surveys (10/19, 53%). Two articles discussed the findings of 6 IVR surveys (6/19, 32%). Three SMS surveys were identified from 2 articles (3/19, 16%). Approximately 63% (12/19) of MPS were delivered to mobile phone numbers collected from previously administered household surveys. The majority of MPS (11/19, 58%) were panel surveys where a cohort of participants, who often were provided a mobile phone upon a face-to-face enrollment, were surveyed multiple times.
Very few reports of population-level MPS were identified. Of the MPS that were identified, the majority of surveys were conducted using CATI. Due to the limited number of identified IVR and SMS surveys, the relative advantages and disadvantages among the three survey modalities cannot be adequately assessed. The majority of MPS were sent to mobile phone numbers that were collected from a previously administered household survey. There is limited evidence on whether a random digit dialing (RDD) approach or a simple random sample of mobile network provided list of numbers can produce a population representative survey.