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-Cascading effects between taxes
-Determination of household expenditures net of implicit commodity taxes
The SPSM is written in the C++ programming language. Changes to the tax/transfer model
algorithms can be made in two distinct ways: the "black box" or the "glass box" mode. The
majority of SPSM analyses operates in "black box" mode.
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When using the model in the black box mode, a user would specify changes to one or
more of the over 800 tax/transfer parameters. In this mode the user can change levels and
rates affecting various benefits, taxes, and eligibility requirements, and can also specify a
sub-population that will be modeled.
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The glass box mode is designed for use by persons who wish to develop entirely new
algorithms or to change existing algorithms. Glass box users can write a new (or modify
an existing) algorithm in the C++ programming language, and then recompile the model.
The new model may then be used in black box mode. The user need not be a C++
language expert in order to use glass box mode, but should be experienced with some
high level computer language.
The SPSD/M may be projected to represent a variety of different years using a method of
static aging. A set of database adjustment algorithms and alternate weight files are
included with the model to this end. The algorithms allow the user to "grow" or project the
value of the money items on the base year database to some future year. The user can
specify a series of growth rates which are then applied by the model. In most cases a single
scaling factor is applied. However, for certain important or complex variables more
complicated rates are applied. For example, employment earnings are "grown" by rates
specific to province and sex of the individual. These algorithms are used in conjunction with
annual demographic weight files included as part of the database.
Users may add their own adjustment routines to augment or even replace the supplied
adjustment algorithms. For example, if users wish to grow employment income at rates
differing by age and sex, they could set the existing employment income scaling parameters
to one and create a new income scaling algorithm.
SOFTWARE AND FACILITIES
The SPSD/M comes with a powerful software support environment designed to enhance the
range, speed and ease of policy analysis in both black box and glass box modes. The
comprehensive and flexible set of reporting options allow for detailed examination and
verification of the database, algorithms and results. The software has been designed to work
in an integrated fashion at different levels of analysis (e.g. household, census family,
individual).
The Visual SPSM program allows for people unfamiliar with the command environment to
use the SPSM by providing a Windows based method to modify parameters, run the model,
and examine the resulting output. A help facility provides information on the use of the
model as well as a handy reference to parameter lists. Some highlights of the model are:
Introduction and Overview Guide
SPSD/M Version 16.1
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