Among various structures in Stata for cycling through lists (whether lists of variable names, numbers, or arbitrary strings) are foreach and forvalues, introduced in Stata 7 in 2001, and for, introduced in Stata 3.1 in 1992, and revised in 5.0 (1997) and 6.0 (1999). Typically, each member of the...

Data for people in a family, firms in a sector, or members of any kind of group are often analyzed using data for the other members in each group. Examples are the number of older children for each child in a family or the mean investment of other firms in the same year. Many such problems yield...

Circular data are a large class of directional data, which are of interest to scientists in many fields, including biologists (movements of migrating animals), meteorologists (winds), geologists (directions of joints and faults), and geomorphologists (landforms, oriented stones). These examples...

The Stata Technical Bulletin (STB ) started publication in March 1991 and ceased in May 2001, after 61 bimonthly issues. It has been succeeded by the Stata Journal (SJ), of which two quarterly issues have so far appeared, 1(1) for the last quarter of 2001 and 2(1) for the first of 2002. Although...

Graphics and categorical data are odd bedfellows. A pie chart of the frequencies of a categorical variable may be the first statistical technique taught to young children, and there is a very substantial if self-contained literature on biplots and related methods. Yet in between many texts and...