Don't always believe what you read in the newspapers or what gets spread around on Facebook. Child psychologists are alarmed by recent infant sleep-training study.
Original article posted by Psychologytoday.com by Darcia Narvaez Ph.D. on June 12th, 2016
A flawed Australian study recently made national news. The researchers made extreme and exaggerated claims regarding infants. The researchers claimed two interventions during three months on a total of 7 babies in each group appeared effective with no detrimental effects on the infants or the families. Their claims were based on poor data, a flawed design, and misleading information. Disregarding basic research standards, the researchers used inconsistent, invalid, and subjective data.
"The sad result is misinformation and confusion to pediatricians and the parents who look to authorities for information and advice. We are all misguided by these easily-published, substandard, and inaccurate studies."
Child psychologists and other professionals are alarmed by these unsupported and inflated claims. Below is a response to the multiple errors in the study, “Behavioral Interventions for Sleep Problems: A Randomized Controlled Trial.” The article was published in Pediatrics: Journal of American Academy of Pediatrics, volume 132, May 24, 2016.
This study is multiply flawed but still makes generalizations for all babies based on two experimental groups with only 7 babies in each group at the end of a three-month study. The flaws in the study listed below would render the paper unpublishable in other venues.
Data flaws include:
• 50% drop out rate: unacceptably high. No comparison of dropouts with retained, which would be required in top psychology journals. Are the retained participants representative of the group demographically? Was there a pattern of child age that stayed in or dropped out of the study? What missing data handling methods were used for the analysis? What missingness mechanisms were assumed for the analyses? If the missing data handling methods used in the paper are not appropriate, the results would be biased and misleading.
• Small sample size at beginning and even smaller at the end—the graduated extinction (cry it out) intervention had a sample size of n=7 at one month and n-7 at three months due to drop-outs. The fading intervention had a sample size of n=10 at one month and n= 7 at three months.
• Failure to collect real-time stress measures, i.e., cortisol data during nocturnal treatment. Researchers did not measure acute stress during interventions.
• Treatment success based on self-reports and sleep diaries, possible sources of bias. Parental responses can be influenced by educational levels, psychopathology, parenting styles and family dynamics, as well as desire to be successful in the study.
* Lack of diagnostic criteria or definition of “sleep problems.” Parents answered Yes/No to the question: “Does your infant have a sleep problem?”
* No intervention fidelity check. Did the parents do what they were told to do? Researchers failed to verify that interventions were delivered as designed. Parents underwent treatment sessions and collected cortisol samples morning and afternoons. Parents received a booklet describing interventions and cell phone support, however, no data was recorded for the calls.
• Inflated Type 1 error (unreplicable chance findings that are not actually “true”) from running too many tests.
• Unclear data analysis models (linear mixed model regressions) making it hard to judge validity of analysis. Without more information about the models, it is difficult to evaluate whether the models were appropriate for the analyses. For example, are linear trends implied by the linear mixed models? If so, the trends shown in Figure 2, however, do not look linear. Therefore, the models might be mis-specified ones for the data.
• Critical details about the results are missing. For example, they had “significant interactions for sleep latency.” What kind of interactions are they referring to?
* Problems with internal validity. Researchers failed to address confounding variables. There was a range of ages, with average infant age of 10.8 months. The study duration was three months. Infant night time awakenings typically diminish by the first year of life. Cortisol responses also diminish from four months of age.
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