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Community Cellular Networks: An Experimental Evaluation in the Philippines
Last registered on August 07, 2019


Trial Information
General Information
Community Cellular Networks: An Experimental Evaluation in the Philippines
Initial registration date
August 07, 2019
Last updated
August 07, 2019 5:05 PM EDT
Primary Investigator
University of California, Berkeley
Other Primary Investigator(s)
PI Affiliation
University of California, Berkeley
PI Affiliation
Federal Reserve Board of Governors
PI Affiliation
University of California, Davis
PI Affiliation
University of California, Berkeley
Additional Trial Information
On going
Start date
End date
Secondary IDs
Despite the rapid expansion of mobile coverage in the developing world, roughly 10% of the world's population still lives beyond the reach of a cell tower and all of the platforms, products, and services that cell towers make possible. This study investigates the impact of a new type of cellular connectivity designed specifically to address the "last mile" problem: the Community Cellular Network. Built on open-source technology, the Community Cellular Network provides community-owned cellular infrastructure at one-tenth of the cost of traditional mobile towers.
Our goal is to develop a deeper understanding of the social and economic impacts of first-time access to a cellular network in isolated communities in the Philippines. We use a two-stage randomized control trial in which we (i) randomly assign villages to receive or not receive a new cell tower; and (ii) within treated villages, randomize the price that households paid to access these networks. This pre-analysis plan describes how we plan to study the impacts of cellular access on social network structure, and several social and economic outcomes.
External Link(s)
Registration Citation
Blumenstock, Joshua et al. 2019. "Community Cellular Networks: An Experimental Evaluation in the Philippines." AEA RCT Registry. August 07. https://doi.org/10.1257/rct.4469-1.0.
Former Citation
Blumenstock, Joshua et al. 2019. "Community Cellular Networks: An Experimental Evaluation in the Philippines." AEA RCT Registry. August 07. http://www.socialscienceregistry.org/trials/4469/history/51405.
Sponsors & Partners

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Experimental Details
1. Community Cellular Networks
The primary intervention is the installation of cellphone towers in selected sites. Researchers from the University of California, Berkeley developed a new mobile phone technology --- the Community Cellular Network (CCN) --- that provides local coverage at one-tenth of the cost of traditional mobile towers. The CCN is designed specifically for rural settings with intermittent power and is designed to be owned and maintained by local community members with modest technical training (Heimerl and Brewer, 2010). Over the past several years, we have been collaborating with those who developed the CCN and researchers at the University of the Philippines, Diliman, to deploy CCNs in several remote and isolated villages in the Philippines.

2. Price Promotions
We offered promotions to customers through a second randomized experiment. The first dimension is a free credit of 100 Pesos loaded directly to the customer's balance. The second dimension is a type of tariff discount provided to customers. 50% tariff discounts were applied to either local on-network calls or long-distance calls. All customers, including those in the promo control group, received five free long-distance text messages. To account for potential sharing of phones within the household, treatment assignment was done at the household level.
Intervention Start Date
Intervention End Date
Primary Outcomes
Primary Outcomes (end points)
We will test four families of hypotheses: (i) access to communications, (ii) social networks, (iii) informedness, and (iv) economic outcomes. Each family contains one or more specific outcomes that we hypothesize are likely to be impacted by treatment.

Within the family access to communications, we have one hypothesis:
1. Increased access to communications

Within the family social networks, we have two hypotheses:
2. Increased social connectedness - local
3. Increased social connectedness - long-distance

Within the family informedness, we have two hypotheses:
4. Increased informedness
5. Increased disaster preparedness

Finally, within the family economic outcomes, we have ?ve hypotheses:
6. Increased market access
7. Changed migration
8. Changed remittances and risk-sharing
9. Changed income and expenditures
10. Changed subjective well-being
Primary Outcomes (explanation)
See pre-analysis plan for detailed explanations.
Secondary Outcomes
Secondary Outcomes (end points)
We have two secondary families of outcomes

The first is political economy, which has hypotheses:
1. Increased political participation
2. Increased political manipulation
3. Increased political-economic knowledge

The second is intra-household decision-making, which has hypotheses:
4. Increased role of women in income decisions
5. Increased role of women in fishing/agriculture decisions
6. Increased role of women in control of resources
7. Decreased spousal difference in reported fish/crop prices
Secondary Outcomes (explanation)
See pre-analysis plan for detailed explanations.
Experimental Design
Experimental Design
By leveraging a new low-cost technology, and by cultivating strong local relationships, we created a truly unique opportunity to conduct a randomized control trial of Community Cellular Networks in a set of 14 geographically isolated villages in the Aurora province of the Philippines. The randomized control trial had two stages. The first was a village-level treatment, where a "staggered roll-out" design randomly determined which seven of the 14 villages received a CCN between September 2017 and September 2019, as well as the timing of each installation. The second stage was a household-level treatment, through which we reduced the cost of making phone calls and sending text messages to specific households. This second stage will allow us to precisely estimate the demand for cellular connectivity (and all that comes with it), and will create random household-level variation in communication costs, which we can in turn use to identify the impact of connectivity on other outcomes.
Experimental Design Details
Randomization Method
Community Cellular Networks - Matched-pairs randomization done on a computer using the R package, nbpMatching, from Beck, Lu, and Greevy (2016)
Price Promotions - Random assignment to price promotions done in Stata.
Randomization Unit
Community Cellular Networks - randomized at the village/site level
Price Promotions - Randomized at the household level
Was the treatment clustered?
Experiment Characteristics
Sample size: planned number of clusters
Community Cellular Networks - 14 sites
Price Promotions - 1131 eligible households
Sample size: planned number of observations
Community Cellular Networks - 2,370 households Price Promotions - 6,613 adults
Sample size (or number of clusters) by treatment arms
Community Cellular Networks -
1. Treatment (7 sites)
2. Control (7)

Price Promotions -
1. No promotions (187 households)
2. Free phone credit (191)
3. Local discount (183)
4. Local discount plus free credit (186)
5. Long distance discount (191)
6. Long distance discount plus free credit (193)
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Supporting Documents and Materials

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IRB Name
University of California Berkeley
IRB Approval Date
IRB Approval Number
Analysis Plan
Analysis Plan Documents

MD5: 70db31e3fcb394b9327029c9a6daff60

SHA1: 53d0da229f36bee4a1ded28a44f8f71117fb95de

Uploaded At: August 07, 2019

Post Trial Information
Study Withdrawal
Is the intervention completed?
Is data collection complete?
Data Publication
Data Publication
Is public data available?
Program Files
Program Files
Reports, Papers & Other Materials
Relevant Paper(s)