Jewish Community Studies in the Twenty-First Century.

Periodic measurement of the size and behaviors of the Jewish population is of vital importance to Jewish communal planners, both nationally and in communities throughout the United States. Methodological design decisions, such as the choice of a sampling frame, mode of data collection, nonresponse follow-up protocols, and definition of eligibility can have significant impacts on population estimates. This paper demonstrates how two studies, one national and one for the Jewish Federation of Greater Philadelphia used the current state-of-the-art address-based sampling methodology and other methodological improvements to significantly increase coverage and reduce bias in the survey results compared to other methodologies.

The enigma of number: why children find the meanings of even small number words hard to learn and how we can help them do better.

Although number words are common in everyday speech, learning their meanings is an arduous, drawn-out process for most children, and the source of this delay has long been the subject of inquiry. Children begin by identifying the few small numerosities that can be named without counting, and this has prompted further debate over whether there is a specific, capacity-limited system for representing these small sets, or whether smaller and larger sets are both represented by the same system. Here we present a formal, computational analysis of number learning that offers a possible solution to both puzzles.