introduction to research methodology, Study notes of Research Methodology

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Collecting Evidence:

Quantitative Instrument Reliability

Objectives

• By the end of this lesson, you will be

prepared to:

1. Discuss the types of instrument reliability.

2. Identify information provided about

reliability of quantitative measures when

appraising quantitative research studies.

Correlation Coeffficient

• An estimate that indicates the reliability of an

instrument

• (^) +1 (perfect reliability)
• (^) 0.80 or above is considered the lowest acceptable

for a well-developed measurement tool

• (^) 0.70 or above acceptable for new instruments
• (^) 0.00 (absence of reliability)

Reliability

Attribute: Type

• (^) Stability: Test-Retest • (^) New instrument given 2 times; strong + correlations = good reliability How Determined

Attribute Type

• (^) Equivalence: Interrater reliability How Determined
• (^) 2 observers rate same event; strong + correlations = good reliability

Attribute Type

• (^) Internal Consistency: Split-half How Determined
• (^) Divide items into 2 instruments; give both halves; compare using Spearman-Brown formula.

• (^) Internal Consistency: Kuder-Richardson (K-2R)
• (^) Internal Consistency: Cronbach’s alpha How Determined
• (^) (Used for dichotomous items) All items simultaneously compared via a computer to obtain single correlation. 0.000 and 1.000; a value close to +1.000 indicates a high degree of reliability.
• (^) (Used for interval or ratio items) All items simultaneously compared to obtain single correlation. 0.7 indicates good/acceptable reliabiity; 0.9 or higher indicates excellent reliability. Attribute: Type

Appraising Quantitative Methods

• (^) What are the concepts/variables being

measured?

• (^) Does the data collection method fit the study

variables?

• (^) Is there detail about the intervention and control

groups?

• (^) What steps were taken to minimize

measurement error?

References

• Dougherty, J. (2015). Collecting evidence. In

N. A. Schmidt & J.M Brown, Evidence-based

practice for nurses: Appraisal and application

of research (

nd

Ed.), (pp. 263-288).