We know of no method to overcome this problem except to select samples of equal size, which was not a feature of the DHS sampling design. One may also question if the subgroup sample sizes are large

enough. This is an important and relevant question when planning a study and when the magnitude of the effect one wishes to detect is specified. Then, sample size may be adjusted to achieve a certain level of statistical power, conventionally 0.80 or greater. However, the KDHS was not designed with such considerations in mind, and sample sizes were determined on the basis of the wish to produce nationally representative samples and with practical data collection limitations in mind. This points to an important limitation of this study, as it is now fairly Screening Library mouse well established that post-study (post hoc) power calculations to aid in the interpretation of results should be avoided FDA-approved Drug Library in vitro [43], [44] and [45]. The post hoc analyses in this article, also called data snooping [46], are perhaps best evaluated in

terms of confidence intervals and not P values: “…the breadth of the interval tells us how confident we can be of the true state of nature being close to the null. Once we have constructed a confidence interval, power calculations yield no additional insights” [44]. Our position is that the sample sizes are what they are, our confidence in our interpretation of the data varies in part as a function of sample sizes, and our level of confidence is reflected in a conventional way, in the reported confidence intervals. A DHS study with larger or smaller samples sizes would have come

to some different conclusions. Here, we are limited to reporting the findings with the data that are actually available. In conclusion, long-term trends in exclusive breastfeeding are improving, whereas trends in early initiation of breastfeeding, complementary feeding and breastfeeding, and bottle-feeding are mostly stagnant. The province where the mother resided was a significant predictor of early initiation of breastfeeding, exclusive breastfeeding, and bottle-feeding. Since 2009, numerous child feeding Carbohydrate education initiatives have been carried out in Kenya. The present findings suggest that such initiatives, which emphasize the importance of exclusive breastfeeding in the first half year of life, should not overlook education that focuses on the vital importance of feeding colostrum, continued breastfeeding up to 2 years of age or beyond, and the avoidance of bottle-feeding when stringent hygiene cannot be practiced due to lack of resources and unhygienic conditions. The results of this study also point to the importance of research to develop a better understanding of how local contexts influence child care and feeding practices.