Look for problems in the data and be prepared to explain why they are problems. Engage in a Discussion with your colleagues and work together to repair the data set by addressing all of the errors. Note that the data set contains a total of 63 errors.
ollecting valid data is an art unto itself. Ensuring that your results are valid and unbiased is a skill beyond the scope of this module. However, even quality data can be corrupted by human error and inattention to detail. Some of the most common data errors include:
- Data that are not read properly
- Dates are interpreted improperly
- Hidden characters that result in improper fields (such as a tab character in a field that looks blank but causes SPSS to classify the field as a “string”)
- SPSS auto-assigning incorrect levels of measurement
- Data that are out of range
- Impossible categories
- Calculating a nonsensical mean (if 1 = blonde, 2 = brunette, 3 = red hair, 4 = black hair, etc., then a mean hair color of 3.1 provides no useful information)
- Lower- and upper-case letters used interchangeably (such as “f” and “F” for sex)
- Inconsistency of measurement and coding
Be sure to review the demonstration video in the Learning Resources, which explains how to identify and fix common data errors. It also discusses specific errors commonly introduced when Excel data are imported into SPSS.
In this Discussion, you work together with a small group of your colleagues, as assigned by the Instructor. The Instructor will post these group assignments in the Announcements area by Day 3 of Week 4. Import the “Module 3 Discussion Data Set” listed in the Learning Resources into SPSS. Look for problems in the data and be prepared to explain why they are problems. Engage in a Discussion with your colleagues and work together to repair the data set by addressing all of the errors. Note that the data set contains a total of 63 errors.
