Most of the variance in diurnal cortisol is attributable to intraindividual variability (IIV), defined as relatively short-term, reversible changes. Multiple methods for measuring IIV have been proposed, and some have already been applied to cortisol IIV. In the present review, measurement methods are described and applied to simulated cortisol data with known underlying differences in IIV and to real cortisol data from first-year law students. More slope variance and more residual or net variance were well captured by their individual standard deviations. Explorations of reliability suggested that 10 slopes and 50 residuals result in reliable and stable estimates of the individual standard deviations. A data-analytic plan for cortisol IIV is provided.
|Number of pages||11|
|State||Published - Apr 1 2017|
Bibliographical noteFunding Information:
This work was made possible by funding from the National Institutes of Health (K02-AG033629, R01-MH61531).
© 2017 Elsevier Ltd
- Intraindividual variability
- Root mean squared successive difference
- Standard deviation
ASJC Scopus subject areas
- Endocrinology, Diabetes and Metabolism
- Endocrine and Autonomic Systems
- Psychiatry and Mental health
- Biological Psychiatry