The 2018 Mozambique Informal Sector Business Survey (ISBS) data was collected by the World Bank Group - Enterprise Analysis Unit. The survey covers three cities, Beira, Maputo and Nampula.
The primary objectives of the survey are: i) to understand the business demographics of the sector in the two cities, and ii) to describe the environment within which these businesses operate. A secondary objective of the survey is to provide an estimate of the number of informal businesses operating in these cities.
Kind of data
Sample survey data [ssd]
Version 01. Edited, anonymous dataset for public distribution.
The survey covers three cities, Beira, Maputo and Nampula.
Unit of analysis
Unit of analysis is informal business, where informality is defined based on whether or not a business is formally registered with the government.
The universe includes informal businesses, where informality is defined based on whether or not a business is formally registered with the government.
Producers and sponsors
World Bank Group (WBG)
World Bank Group
The 2018 Mozambique ISBS uses an innovative technique to survey these businesses. The survey follows an area-based sampling methodology with geographic area rather than an establishment or a business unit as a primary sampling unit. To account for potential clustering of informal business, the survey uses an area-based sampling called (stratified) Adaptive Cluster Sampling (ACS), whereby one selects a sample of starting squares and adaptively samples surrounding squares based on the number of informal firms discovered in the enumerated squares. All informal business in selected squares will be enumerated using a 2 to 3-minutes questionnaire, referred to in this document as the short-form questionnaire. The short form questionnaire is a listing questionnaire where basic information about the business is collected. A randomly selected subset of the enumerated businesses will be given a 20-minutes questionnaire, referred to in this document as the long-form questionnaire.
The survey is adaptive in the sense that if the number of informal units in a square exceeds a predefined threshold, all the squares surrounding the starting square are surveyed, following the same approach of enumeration and randomly conducting the main interview. If one of the surrounding squares exceed the threshold, then the squares surrounding that square in turn are also surveyed. This process continues until either the network is exhausted, or an arbitrary cut-off point is defined.
The first step in the sampling approach is the construction of a spatial grid as the Primary Sampling Units (PSU) frame. The grid covered the total of municipal areas and each cell had a size of 150 by 150 meters. This produced a total of about 24,000 squares between the three cities, excluding squares that are considered inaccessible. The second step was to stratify each grid, with in each city, based on likely concentration of informal business units. The grids were categorized into four strata: three strata of low, medium, and high concentration of informal sector activity, and a market centre. The stratification was based on local knowledge of the survey implementing contractor with approval from the WBG task team leader. The third step in the sampling process was to select a pre-defined number of starting squares from each stratum for enumeration and main data collection.
To estimate population parameters, weights are applied to survey samples. In surveys design following standard random sampling, selection probability of all units is known before the actual data collection. Hence, weights can be derived as the inverse of selection probability.
Computation of sampling weights is a bit involved for Adaptive cluster sampling since final sample size is not known apriori. In ACS, selection probabilities are not known a priori since units are adaptively added to the sample depending on the number of informal units found in a square. In adaptive sampling, one instead talks about empirically derived inclusion probabilities.
Note: Refer to Sampling Weight section in "The 2018 Mozambique Informal Sector Business Survey Dataset" document for further details on sampling weight.
Dates of collection
Mode of data collection
Computer Assisted Personal Interview [capi]
The survey data was collected using a standardized questionnaire, i.e., the long-form questionnaire. The questionnaire was developed building on previous modules used by the Enterprise Analysis Unit of the World Bank to survey informal businesses.
Confidentiality of the survey respondents and the sensitive information they provide is necessary to ensure the greatest degree of survey participation, integrity and confidence in the quality of the data. Surveys are usually carried out in cooperation with business organizations and government agencies promoting job creation and economic growth, but confidentiality is never compromised.
The use of this dataset must be acknowledged using a citation which would include:
- the identification of the Primary Investigator (including country name)
- the full title of the survey and its acronym (when available), and the year(s) of implementation
- the survey reference number
- the source and date of download (for datasets disseminated online).
The World Bank. Mozambique - Informal Sector Business Survey 2018, Ref. MOZ_2018_ISBS_v01_M. Dataset downloaded from https://www.enterprisesurveys.org/portal/login.aspx on [date].
The user of the data acknowledges that the original collector of the data, the authorized distributor of the data, and the relevant funding agency bear no responsibility for use of the data or for interpretations or inferences based upon such uses.