Constructing Africa’s Cities: Estimating the value of construction worker jobs and non-cognitive skills training

Last registered on June 30, 2020


Trial Information

General Information

Constructing Africa’s Cities: Estimating the value of construction worker jobs and non-cognitive skills training
Initial registration date
June 29, 2020
Last updated
June 30, 2020, 12:14 PM EDT


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Primary Investigator

Trinity College Dublin

Other Primary Investigator(s)

PI Affiliation
DIME, World Bank
PI Affiliation
Trinity College Dublin

Additional Trial Information

In development
Start date
End date
Secondary IDs
Rapid population growth is a key development challenge facing the African continent in the coming decades. Africa’s population, which currently stands at 1.31 billion, is set to grow to 1.68 billion by 2030. This will place huge demands on many sectors of the economy and raises major concerns about how to provide jobs and livelihoods for Africa’s youth. Rapid population growth and urbanization is also placing substantial demands on Africa’s infrastructure with major investments in public infrastructure, including transport, telecommunications and public housing, crucially needed. The labor-intensive nature of such projects provides an opportunity for job creation in the sector, which is one of the main sectors of employment for young men. However, there is no evidence of the effects of jobs created in big infrastructure projects. The central question underlying this project is what the returns from such job opportunities are.

The setting for our project is Dakar, Senegal. The Government of Senegal (GoS) has recognized that improving urban mobility in the Greater Dakar Area (GDA) is of crucial importance for the development of the Senegalese economy, and it has adopted a comprehensive 5-year plan to address some of the challenges that the sector faces. One of the flagship projects of this plan, with strong presidential support, is a modern bus transport system with high level of service (BRT) linking the city center to the north of the city. Construction on the BRT will begin in June 2020 and is estimated to continue for 20 months. It is expected that there will be between 2000 and 3000 workers employed in the construction of the BRT during this period. Given the large scale of this project, in terms of both cost and number of workers, we aim to study the impact of the jobs created on the welfare of the workers that are hired and their medium-term future employment outcomes. With the BRT construction expected to have additional phases and with plans to replicate the project in other west African cities, it is important to understand the costs and benefits incurred by the construction workers in order to understand whether and how, in future phases of this project and in future infrastructure projects more generally, costs can be minimized for workers and benefits can be increased through complementary programs. We will collaborate with CRBC, the contractor selected for the construction of the BRT.

Using a randomized controlled trial, we will test the impact of receiving a job offer to work on this project. We use the fact that there are much fewer jobs than there are eligible workers to randomly assign jobs to applicants thus creating a control group of workers who do not get a job. In addition to testing the impact of receiving a job on one of these infrastructure projects, we will also test the impact of a complementary training intervention. The intervention is based on a pilot study that the research team just completed which provided non-cognitive skills training (conscientiousness) to workers involved in the construction of the railway express line (TER) (AEA Trial Registry Number AEARCTR-0004043). The main purpose of the pilot study was to provide learning and a proof of concept for this larger study linked with the construction of the BRT. We are now waiting on the end-line data to evaluate the impact of training, but our mid-line findings suggest some improvement in conscientiousness indicators.

Our project will contribute to four key strands of academic literature. First, recent evidence using micro survey data across countries shows that compared to high-income countries, labor markets in low-income countries are characterized by higher turnover rates, steeper tenure profiles, flatter experience profiles and significant matching frictions (Donovan et al 2020, Bicks et al 2018, Abebe et al 2020). Donovan et al (2019) argue that the high turnover rates and steeper tenure profiles are consistent with theories of endogenous separation, proposing the learning model of Jovanovic (1979) and the job ladder model of Burdett and Mortensen (1998). The randomization of the job offer, in combination with detailed data on key variables such as match quality, search intensity and outside offers, allows us to understand the role of endogenous separation for labor market outcomes in low-income countries. This enables us to test, for example, whether match quality leads to a stronger wage-tenure relationship, as well as the role of search intensity and outside offers for labor market outcomes. Second, we contribute to the broader literature examining the impact of transportation investments on welfare since while job creation is cited as a benefit of these projects, there has been no in-depth examination of this claim. Third, we will contribute to the literature on the impact of worker training considering the dynamic impacts of training beyond the lifecycle of the contract. Fourth, we will add to the small but growing literature on the role of non-cognitive skills and skill matching. The results of this impact evaluation will directly inform policy makers in Senegal and in other countries on how to increase the short and medium-term benefits that arise from job creation related to transport and infrastructure projects more generally through complementary investments.
External Link(s)

Registration Citation

Kirchberger, Martina, Sveta Milusheva and Carol Newman. 2020. "Constructing Africa’s Cities: Estimating the value of construction worker jobs and non-cognitive skills training ." AEA RCT Registry. June 30.
Experimental Details


The study will involve two main components:
1) Impact evaluation of employment in the construction of the BRT on the welfare of workers
2) Impact evaluation of the provision of non-cognitive skills training for workers involved in unskilled tasks in the construction of the BRT

Component 1:
The recruitment of workers for the construction of the BRT is through the local communities. Low skill workers register as interested with their local CIS (Centre d’Information et de Suivi) committee. When construction work begins in a particular area, the construction company will choose workers from that CIS list. By randomizing the order in which the names appear on the list we can randomly select which eligible workers receive a job.

Component 2:
The second component of the study will involve a training intervention on conscientiousness that has been piloted with success as part of the construction of another large infrastructure project in Senegal, the Rapid Express Train (TER) (AEA Trial Registry Number AEARCTR-0004043). We will focus on unskilled workers in positions that require little technical skill but do require that workers are conscientious, attentive, and adhere to the rules and regulations. Building on the knowledge gained from the TER pilot we will design a suitable training course. The TER training consisted of an introductory session on conscientiousness and its importance in the workplace, followed by weekly reminders for six weeks on how to affect the traits of conscientiousness in everyday work life.
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
With the first component of the intervention we will examine the impact of obtaining a construction worker job and the work experience that this brings on worker outcomes including wage, worker retention, promotion, job satisfaction, and later labor market outcomes including whether the worker finds subsequent employment once the current contract ends, the length of time it takes to find a new job, wage at the time of commencing a new job, job satisfaction at new job. The high-frequency data will allow us to examine the transitional dynamics and help estimate the role match quality, search intensity and outside offers play for labor market outcomes of respondents.

For the second component we will test whether providing non-cognitive skills training to a random sample of workers that received the construction sector job leads to improved outcomes on-the-job but also for workers in their future employment. Outcomes will be worker performance, worker retention, wage, promotion, job satisfaction, whether the worker finds subsequent employment once the current contract ends, the length of time it takes to find a new job, wage at the time of commencing a new job, job satisfaction at new job.
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
We will also test the impact of obtaining the job on household welfare.
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
The overarching treatment being tested in this impact evaluation is the randomization of the offer of a construction worker contract. We are aiming to get all lists of potential candidates from all communities. While it is impossible to a priori know the number of applicants who come forth, we estimate that our sample size will include a minimum of 2,000 people. ANSD (Statistical office) Senegal predict that there are approximately 28,000 unemployed individuals of working age in the area of study and potentially 115,000 eligible candidates. Randomization will take place at the individual level.

- 1,000 treatment workers will be offered a job to work on the construction of the BRT
- At minimum 1,000 control workers, although eligible, will not be offered a contract

Randomization into the training intervention will happen within the 1,000 treatment workers that receive a job to work on the BRT construction with 500 workers assigned to the treatment group.

The primary instruments for data collection will be a baseline and end-line surveys of all workers in treatment and control groups along with high-frequency phone interviews that will be conducted with all participants on a monthly basis to collect key labor market outcomes.
It is expected that the baseline survey will begin in July 2020. It will take place on a rolling basis as the area under construction expands and new lists are drawn up. All workers will be surveyed before the job offer is made. The training intervention will also take place on a rolling basis and will begin after an individual has been hired. The high-frequency phone surveys will take place monthly for all participants in the study. The end-line phone survey will be carried out one year after the start of the contract.
Experimental Design Details
Not available
Randomization Method
The recruitment of workers for the construction of the BRT is through the local communities. Low skill workers register as interested with their local CIS (Centre d’Information et de Suivi) committee. In some cases, the lists will be compiled by the local townhall or the construction company where there is no CIS. We will use the same approach to randomizing the job offers from these lists. These committees were organized by CETUD, the government agency in charge of overseeing the construction of the BRT with the goal of engaging the local communities and ensuring buy-in from these communities. The CIS board consists of volunteers, usually those that are well-known in the community such as the neighborhood chiefs. Those in the community interested in working on the BRT go to a member of the CIS board and let him or her know, and the board members puts the person on a registry list of interested people. CETUD organizes community sensitization meetings before work is about to start in an area, and these meetings are when those in the local community are told about the potential job opportunities and the process for expressing interest in these jobs through the CIS. Individuals are only allowed to apply to one list and their address is recorded at time of registration to ensure that only those living within the area of the CIS apply for the list.

When construction is underway in a particular area, the construction company will choose workers from that CIS list. Companies do this kind of local recruitment in order to engage the local communities and ensure that work opportunities are somewhat shared among different parts of the city. After an application list has closed and before hiring has begun, we will work with the Community Leaders in each area to draw up a list of eligible workers. From this list, workers will be ordered randomly. We will stratify by age and gender. This is the order in which the names will be given to the construction company and they will give job offers to workers in this order. The fact that the jobs being offered require very basic skills, the construction company have no specific preference on what type of person they hire so long as the age condition is met. Given that there are more workers than there are jobs available, those workers that are not selected will be used as the control group. All eligible workers on the list will be surveyed before the construction starts to gather baseline information.

Of the 1,000 construction workers in our sample offered a job we will randomly select 500 to take part in the training intervention. We will also stratify by CIS (community), age and gender.
Randomization Unit
The unit of randomization is the individual.
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
Minimum 2000 individuals
Sample size: planned number of observations
Minimum 2000 individuals
Sample size (or number of clusters) by treatment arms
1000 individuals to receive a construction worker job and 500 of those to receive the training intervention.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
To determine the appropriate sample size, we consider two main outcomes: wage income and worker retention. The data collected during the pilot of the TER allow us to determine the power that the BRT study will be able to detect. With an average daily wage of 4251.9 FCFA and a standard deviation of 2003.3 FCFA, we can detect an effect size of 5 percent with 80% power. To date, there has been little experimental evidence on the impact of job offers. Blattman and Dercon (2016) find no average treatment effect of the job offer on earnings, while Alfonsi et al (2020) find a treatment effect of 34% and 20% for the vocational training and the firm training, respectively. Having the power to detect effect sizes of 5 percent thus seems reasonable. For the complementary intervention, the pilot study conducted for the TER allowed us to estimate a measure of conscientiousness for the particular population of construction workers in Senegal. We use an average conscientiousness level of 4.659 and standard deviation of 0.693. Given we will have both baseline and follow-up data, we assume a correlation between the two of 0.8 since data will be collected on the same individuals within a short period, and we expect personality traits to be persistent over time. With an alpha of 0.05, 500 individuals in treatment and 500 individuals in control, we find that we have 80% power to detect an effect size of 0.1063. Given that in the literature an effect size of 0.15 to 0.19 is detected, we can be confident that the current sample size enables us to detect a significant effect.

Institutional Review Boards (IRBs)

IRB Name
Faculty of Arts, Humanities and Social Sciences, Research Ethics Committee, Trinity College Dublin
IRB Approval Date
IRB Approval Number