Although the item count technique is useful in surveys with sensitive questions, privacy of those respondents who possess the sensitive characteristic of interest may not be well protected due to a defect in its original design. In this article, we propose two new survey designs (namely the Poisson item count technique and negative binomial item count technique) which replace several independent Bernoulli random variables required by the original item count technique with a single Poisson or negative binomial random variable, respectively. The proposed models not only provide closed form variance estimate and confidence interval within [0, 1] for the sensitive proportion, but also simplify the survey design of the original item count technique. Most importantly, the new designs do not leak respondents’ privacy. Empirical results show that the proposed techniques perform satisfactorily in the sense that it yields accurate parameter estimate and confidence interval.

Zeros in compositional data are very common and can be classified into rounded and essential zeros. The rounded zero refers to a small proportion or below detection limit value, while the essential zero refers to the complete absence of the component in the composition. In this article, we propose a new framework for analyzing compositional data with zero entries by introducing a stochastic representation. In particular, a new distribution, namely the Dirichlet composition distribution, is developed to accommodate the possible essential‐zero feature in compositional data. We derive its distributional properties (e.g., its moments). The calculation of maximum likelihood estimates via the Expectation‐Maximization (EM) algorithm will be proposed. The regression model based on the new Dirichlet composition distribution will be considered. Simulation studies are conducted to evaluate the performance of the proposed methodologies. Finally, our method is employed to analyze a dataset of fluorescence in situ hybridization (FISH) for chromosome detection.

We present a case of Iatrogenic twin anemia–polycythemia sequence (TAPS) post-amnioreduction in twin-twin transfusion syndrome at 32 gestational weeks. Slight middle cerebral artery (MCA) peak systolic velocity (PSV) discrepancy was present 3 days after the amnioreduction, with MCA PSV around 1.5 MoM of the doner and 1.0 MoM of the recipient. Eighteen days after the amnioreduction, though MCA PSV remained stable, placental dichotomy, starry-sky liver of the recipient and small amount of right pleural effusion of donor were noted. TAPS was diagnosed and postnatal examination of the twins and the placenta confirmed it. We conjectured that the decompression of the placenta after the sudden reduction of amniotic fluid volume may cause the patency of the tiny anastomoses, resulting in the TAPS.