Effect of infection control measures on the frequency of diarrheal episodes in child care: a randomized, controlled trial.

Background: Diarrheal infections are common in children who attend child care, and preventing transmission of disease in this setting depends on actions by child care staff. We set out to discover whether transmission of gastrointestinal infections in child care could be reduced by improved infection control procedures.

Methods: We performed a cluster randomized, controlled trial of an infection control intervention conducted in child care centers for 1 city in Australia.

Effect of infection control measures on the frequency of upper respiratory infection in child care: a randomized, controlled trial.

Background: Acute upper respiratory infections are common in children who attend child care, and preventing transmission of disease in this setting depends on actions by child care staff. We set out to discover whether transmission of respiratory infections in child care could be reduced by improved infection control procedures.

Methods: We performed a cluster, randomized, controlled trial of an infection control intervention conducted in child care centers in 1 city in Australia.

ML and REML estimation in survival analysis with time dependent correlated frailty.

In the study of multiple failure times for the same subjects, for example, recurrent infections for patients with a given disease, there are often subject effects, that is, subjects have different risks that cannot be explained by known covariates. Standard methods, which ignore subject effects, lead to overestimation of precision. The frailty model for subject effects is better, but can be insufficient, because it assumes that subject effects are constant over time.

Threshold models in a methadone programme evaluation.

The degree of non-compliance with a methadone programme is such that a zero is often recorded as the response variable. Such outcome variables cannot be transformed to normality in order to investigate a regression relationship between the response variable and various risk or treatment variables. The presence of a random effect as well in this regression causes added difficulty in the analysis.