Transformations

From Survey Analysis
Jump to: navigation, search

Data transformation is the process of changing the data in some way. More formally, a transformation involves creating a new variable or set of variables from an existing variable or set of variables.

Contents

Objectives of transformation

Data transformation is undertaken with the following objectives:

Standard transformations of a categorical variable

A categorical variable can be transformed in one of two ways:

  1. It can be turned into a numeric variable, by coming up with some rules about the numeric interpretation of categories. For example:
  2. The categories of a categorical variable can be combined. Most commonly, small categories are merged into larger categories. For example:
    • When a question asks for reasons for a particular behavior, any reasons that are selected by a small number of respondents can be classified as Other.
    • Variables that collect data on Rating Scales may be converted to Binary Variables to make further analysis simpler.

Standard transformations of a numeric variable

FORTHCOMING

Ranks

Log transformations

Trimming

Winsorizing

Multivariate transformations

Dimension reduction

Basis functions

Dummy variables

Polynomials

Orthogonal polynomials

See also

A more up-to-date version of this content is on www.displayr.com.

Personal tools
Namespaces

Variants
Actions
Navigation
Categories
Toolbox