Validity and Reliability of Quantitative Electroencephalography

Abstract

Reliability and validity are statistical concepts that are reviewed and then applied to the field of quantitative electroencephalography (qEEG). The review of the scientific literature demonstrated high levels of split-half and test-retest reliability of qEEG and convincing content and predictive validity as well as other forms of validity. QEEG is distinguished from nonquantitative EEG (''eyeball'' examination of EEG traces), with the latter showing low reliability (e.g., 0.2-0.29) and poor interrater agreement for nonepilepsy evaluation. In contrast, qEEG is greater than 0.9 reliable with as little as 40-s epochs and remains stable with high test-retest reliability over many days and weeks. Predictive validity of qEEG is established by significant and replicable correlations with clinical measures and accurate predictions of outcome and performance on neuropsychological tests. In contrast, non-qEEG or eyeball visual examination of the EEG traces in cases of nonepilepsy has essentially zero predictive validity. Content validity of qEEG is established by correlations with independent measures such as the MRI, PET and SPECT, the Glasgow Coma Score, neuropsychological tests, and so on, where the scientific literature again demonstrates significant correlations between qEEG and independent measures known to be related to various clinical disorders. The ability to test and evaluate the concepts of reliability and validity are demonstrated by mathematical proof and simulation where one can demonstrate test-retest reliability as well as zero physiological validity of coherence and phase differences when using an average reference and Laplacian montage.

Two Criteria for Good Measurements in Research: Validity and Reliability

“…In quantitative research validity is the extent to which any measuring instrument measures what it is intended to measure [Thatcher, 2010]. But, in qualitative research it is when a researcher uses certain procedures to check for the accuracy of the research findings [Creswell, 2014].…”

“…In quantitative research it is possible for a measurement to be reliable, but invalid; however, if a measurement is unreliable, then it cannot be valid [Thatcher, 2010;Twycross & Shields, 2004]. …”

Anteseden Consumers’ Atittude Terhadap Advertising Di Kota Batam

“…Uji validitas konstruk menggunakan statistik analisis faktor. Suatu konstruk dikatakan valid apabila nilai muatan faktor lebih besar atau sama dengan 0,50 (Thatcher, 2010).…”

“…Hal ini menunjukan bahwa seluruh pertanyaan pada variabel credibility, informative, hedonic/ pleasure, good for economy, dan consumers' attitude towards advertising adalah valid, karena factor loading memiliki nilai yang mencapai batas minimum lebih besar atau sama dengan 0,50 (Thatcher, 2010).…”

“…Pengujian reliabilitas konstruk menggunakan metode statistik Cronbach's Alpha. Suatu konstruk memiliki reliabilitas yang baik apabila nilai Cronbach's Alpha lebih besar atau sama dengan 0,60 (Thatcher, 2010 (Thatcher, 2010).…”