Reading

Schmidt & Brown (2021). Evidence-Based Practice for Nurses:

• Chapter 12: Collecting Evidence

Objectives

• Compare nominal, ordinal, interval, and ratio levels of measurement

• Identify examples of systemic and random sources of error

• Anticipate how the time frame, site, and recruitment strategy might affect a quantitative study

• Compare and contrast methods for collecting quantitative data: observation, questionnaires, scales, physiological measures, and electronic medical records (EMRs)

• Define validity and reliability

• Describe tests that researchers use to establish validity and reliability of various measures

• Explain the relationship between data collection and data analysis

Measurement

• = The assignment of numerical values that are objective, standardized, and consistent to characteristics

• Levels of measurement

  • = A system of classifying measurements according to a hierarchy of measurement and the types of statistical tests that are appropriate

  • Four levels of measurement

    • Nominal

      • = The lowest level of measurement whereby data are categorized simply into groups; categorical data

      • Dichotomous

        • = A nominal measurement when only two possible fixed responses exist, such as yes or no

    • Ordinal

      • = A continuum of numeric values where the intervals are not meant to be equal

    • Interval

      • = A continuum of numeric values with equal intervals that lacks an absolute zero

      • e.g. Temperature

    • Ratio

      • = The highest level of measurement that involves numeric values that being at absolute zero and have equal intervals

      • e.g. Body weight

• Measurement Error

  • = The difference between the true score and the observed score

  • Measurement errors can be categorized as systemic errors and random errors

    • Systemic errors

      • = Error that occurs in the same way with each measurement

    • Random errors

      • = Error that occurs by chance during measurement

Collecting Numbers

• Quantitative data are collected through many methods, including (1) observation, (2) instruments and scales, (3) physiological measures, and (4) electronic medical records (EMRs)

  • (1) Observation

    • = A technique of carefully observing phenomena using the five senses to gather data

• (3) Physiological measures

  • = Data obtained from the measurement of biological, chemical, and microbiological phenomena

• (4) Electronic Medical Records (EMRs)

  • Offers readily available and relevant data for a particular site, as well as local, regional, and even national databases

  • Data from EMRs often are used in evidence-based practice and quality improvement (QI) projects

Validity and Reliability of Instruments

What Types of Health Data Do We Collect? (25:05)

Quantitative Analysis Part 1 (15:30)

Note: The first two slides are not covered in this recording, but the rest of the slides are the same.

Looking for Part 2 and Part 3? Go to the Analyzing Data page!