DATA PROCESSING EDITING CODING PROCESSING Data Processing Processing

DATA PROCESSING EDITING, CODING

PROCESSING Data Processing • Processing data is very important step after collecting the data. • The job of the researcher is to analyze and interpret the data. • The purpose of analysis is to draw conclusion. There are two parts in processing the data. (1) Data Analysis (2) Interpretation of data

steps • • • Preparing raw data Coding Editing Tabulation of data Summarising the data Usage of statistical tool.

Overview of the Stages of Data Analysis

EDITING The process of checking and adjusting responses in the completed questionnaires for omissions, legibility, and consistency and readying them for coding and storage

Types of Editing 1. Field Editing • Preliminary editing by a field supervisor on the same day as the interview to catch technical omissions, check legibility of handwriting, and clarify responses that are logically or conceptually inconsistent. 2. In-house Editing • Editing performed by a central office staff; often do more rigorously than field editing

Purpose of Editing 1. For consistency between and among responses 2. For completeness in responses– to reduce effects of non-response 3. To better utilize questions answered out of order 4. To facilitate the coding process

Editing for Completeness • Item Nonresponse • The technical term for an unanswered question on an otherwise complete questionnaire resulting in missing data. • Plug Value • An answer that an editor “plugs in” to replace blanks or missing values so as to permit data analysis; choice of value is based on a predetermined decision rule. • Impute • To fill in a missing data point through the use of a statistical algorithm that provides a best guess for the missing response based on available information.

Facilitating the Coding Process • Data Clean-up • Checking written responses for any stray marks • Editing And Tabulating “Don’t Know” Answers • Legitimate don’t know (no opinion) • Reluctant don’t know (refusal to answer) • Confused don’t know (does not understand)

Editing (cont’d) • • Pitfalls of Editing • Allowing subjectivity to enter into the editing process. § Data editors should be intelligent, experienced, and objective. • Failing to have a systematic procedure for assessing the questionnaires developed by the research analyst § An editor should have clearly defined decision rules to follow. Pretesting Edit • Editing during the pretest stage can prove very valuable for improving questionnaire format, identifying poor instructions or inappropriate question wording.

CODING • The process of identifying and classifying each answer with a numerical score or other character symbol • The numerical score or symbol is called a code, and serves as a rule for interpreting, classifying, and recording data • Identifying responses with codes is necessary if data is to be processed by computer

• Data/ responses are organised into classes or categories and numerals are given to each according to the class it falls

Coding - Continued • Coded data is often stored electronically in the form of a data matrix - a rectangular arrangement of the data into rows (representing cases) and columns (representing variables)

Key Issues in Coding 1. Pre-Coding Fixed-Alternative Questions (FAQs) -Writing codes for FAQs on the questionnaire before the data collection 2. Coding Open-Ended Questions : responses are recorded verbatims. Note the basic or essential aspect of possible responses. Give a number to each aspect 3. Two Rules For Code Construction are: a) Coding categories should be exhaustive b) Coding categories should be mutually exclusive and independent

Issues in Coding - Continued 3. Maintaining a Code Book - A book that identifies each variable in a study, the variable’s description, code name, and position in the data matrix 4. Production Coding - The physical activity of transferring the data from the questionnaire or data collection form [to the computer] after the data has been collected. Sometimes done through a coding sheet – ruled paper drawn to mimic the data matrix 5. Combining Editing and Coding

AFTER CODING …. . 1. Data Entry - The transfer of codes from questionnaires (or coding sheets) to a computer. Often accomplished in one of three ways: a) On-line direct data entry – e. g. as for CATI systems b) Optical scanning – for highly structured questionnaires c) Keyboarding – data entry via a computer keyboard; often requires verification

After Coding - Continued 2. Error Checking – Verifying the accuracy of data entry and checking for some kinds of obvious errors made during the data entry. Often accomplished through frequency analysis.

After Coding - Continued 3. Data Transformation – Converting some of the data from the format in which they were entered to a format most suitable for particular statistical analysis. Often accomplished through re-coding, to: • reverse-score negative (or positive) statements into positive (or negative) statements; • collapse the number of categories of a variable

Tabulation • • Process of summarising raw data and displaying it in compact form for further analysis. The results are summarized in the form of statistical tables. The raw data is divided into groups and subgroups. The counting and placing of data in particular group and subgroup are done. Tabulation involves (1) Sorting and counting (2) Summarizing of data Tabulation may be of 2 types (1) simple tabulation (2) cross tabulation. In simple tabulation, a single variable is counted. Cross tabulation includes 2 or more variables, which are treated simultaneously. Tabulation can be done entirely by hand or by machine or both hand machine.

• Table should include the following 1. table number 2. title 3. caption (column heading) 4. stub (row heading) 5. head note 6. foot note

ONE-WAY TABLE DIVISION Sukkur POPULATION (Millions) 10. 875968 14. 186954 12. 994401

TWO-WAY TABLE DIVISION POPULATION (Millions) Male Sukkur Female Total

Summarising • Summarizing the data includes (1) Classification of data (2)Frequency distribution (3) Use of appropriate statistical tool