Programación de Harmonizer: aplicación del tratamiento armónico

SAMOD is a national level microsimulation model that has been designed to be flexible enough

to take into account the particularities of different policies but also to provide a common

framework for the implementation of policies and the production of results (Wilkinson et al.,

2009). This guaranteed comparability of outputs and transferability of policies hence makes it

possible to analyse the effects of the application of policies on the national level.

SAMOD can calculate what benefits and tax credits individuals and households are entitled to

under hypothetical tax and benefit systems. Accordingly, the study used the simulated data on

149 the distribution of household disposable income to calculate the number of children living in

poverty, based on a selected poverty line of R450 per capita per month.

5.5.1. Data source

Data from a household survey are classified into the categories of households contained in the

structural component of the model. The current version of SAMOD (version 1.1 of February

2009), data relating to 31st July 2007 and policy systems (i.e. tax and benefit rules) relating to

August 2008 were used throughout the study. The poverty and inequalities of people living in

households with children and income distribution indicators were then calculated with these data.

The micro-data used in SAMOD were derived from the 2000 and 2005/6 SA Income and

Expenditure Survey, the 2000 and 2006 Labour Force Surveys and the 2007 Community Survey

(Wilkinson et al., 2009). These surveys were the only large household surveys with the necessary combination of demographic and income information conducted recently. The data

has proved to be a very reliable source for the purpose of income analysis and microsimulation

(Wilkinson et al., 2009).

5.5.2. Research procedures

In this study, the research procedure reflects the statement of the problem and the different types

of methodologies employed. Moreover, it also shows the appropriate ways and relevant steps

that were used throughout the research. The major procedures included the following:

• A literature review study, which included both primary and secondary data from different sources. Its aim was to review the critical points of current knowledge on and methodological

approaches to microsimulation.

150 • Partners’ permission: SAMOD is jointly owned by the South African Department of Social Development, the University of Oxford and the University of Essex. All three partners are

required to give their permission for individuals or organisations outside these three

organisations to use the model. Hence, the research process started after the three partners

had given permission and approval to use the model.

• Practical experiences: Before commencing with the use of SAMOD, theoretical and practical experiences were gained in terms of operating the data model and interpreting the outputs.

This made the use of the model and communication easy at all levels and created a clear

understanding of microsimulation,

• Installation of SAMOD: The entire content of the SAMOD CD was copied and all the folders were pasted into a new location. This was done onto the C:\ drive into a folder named

SAMOD.

• Navigating: The SAMOD file was accessed on the computer by opening the Excel file named SAMOD.xls in the folder C:\SAMOD. This opens the main navigation screen known as the

SAMOD operating system. From here all other parts of the model, including documentation

and tools to run the model to produce output, were accessed.

• Dataset: In order to calculate taxes and benefits for the year 2008, one would use the 2008 policy rules together with data referring to the year 2008. However, corresponding data were

not available and, even if they had been, preparing and integrating new data into the model

would have been a very laborious task. Therefore, government 2008 policy rules on 2007

population baseline datasets were used for simulating various policy scenarios.

151 • Calculations: The micro-output file, SAMOD output, is essentially based on two inputs: (a) household micro-data and (b) rules on how to calculate taxes and benefits. These rules are

stored in parameter files. Using these two information sources, the model calculated all taxes

and benefits that had been built into the simulation. These calculations were carried out for

each household in the dataset and the result was written to a micro-output file.

• Measurement: The poverty impact of various scenarios was modelled using the Foster-Greer- Thorbecke (FGT) index of poverty measurement and societal welfare inequalities were

measured using the Gini co-efficient.

• Data processing and presentation: Computer software was used to place, into categories, the correlation and examination of relationships, analyses and data presentation, using tables, bar

graphs, text, pictures, and others.

5.5.3. Baseline dataset

In order to calculate taxes and benefits, the study used the 2008 policy rules on the 2007

population baseline. Corresponding data were not available and integrating new data into the

model was thought to be too laborious a task. Therefore, 2007 micro-data was used for

simulating policy year 2008. These system-dataset combinations formed the baseline of the

dataset. SAMOD was run using the 2008 policy rules on the 2007 population baseline and the

output data were stored in the folder indicated in the output path field.