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Data Preparation

Data Preparation. Data Entry. Some thumb rules Maintaining records of forms to be able to go back Person giving two (or more) responses Encircling is a better way How to resolve two logically inconsistent responses (.e.g., jobless as well as employed)?

cameran-barrett
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Data Preparation

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  1. Data Preparation

  2. Data Entry • Some thumb rules • Maintaining records of forms to be able to go back • Person giving two (or more) responses • Encircling is a better way • How to resolve two logically inconsistent responses (.e.g., jobless as well as employed)? • Coding of open-ended responses: Illustration of a coding scheme • How to find out the goodness of such a coding scheme • Mutually exclusive • Exhaustive

  3. Don’t Know Responses • Consider following questions: • Who invented telephone? • Do you believe in the new fiscal policies? • Do you like your job? • How many movies did you watch last year? • Remedy: • Think about the possible reasons behind DK response beforehand.

  4. Qualitative Data • Recording in own voice • Transcribing or not? • Line numbering for QDA

  5. Quantitative Data Examination • Examination of variables: • Histogram • Scatterplot and scatterplot matrix • Data transformation, in case of not meeting assumptions such as normality or homoscedasticity • For flat distributions: Generally 1/X • For skewed distributions: X^2 or X^3 or taking log • Missing data • List wise deletion • Pair-wise deletion • Replacement with mean

  6. Missing Data • More problematic in longitudinal research • Techniques used assume complete data Graham, 2009

  7. Outlier Detection • Should use all techniques • Univariate: • For small sample size (<=80), typically standard score of 2.5 or more • For larger sample size: standard score of 4 or more • Bivariate: Mostly dependent-independent pairs • Multivariate: Mahalanobis D^2 • What to do with them?

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