A unit of study that introduces measuring as a way of collecting data is presented. Suitable for students in grades 3 and 4, it provides a foundation for further work in statistics and data analysis. The investigations may extend from one to four class sessions and are grouped into three parts: "Introduction to Measurement"; "Using Standard Measures"; and "A Project in Data Analysis." An overview of the investigation, session activities, dialogue boxes, and teacher notes are included in each investigation. The major goals developed in each part of this guide are: (1) moving through space and counting the movements; (2) comparing units of measure; (3) estimating distances; (4) defining a measurement method; (5) writing directions involving distances; (6) recording and displaying the results of measurement; (7) experiencing a need to standardize; (8) understanding that standard measures were invented to solve real data collection problems; (9) estimating lengths; (10) measuring accurately, using feet and inches; (11) describing the shape of the data; (12) analyzing data through landmarks and features of the data; (13) using standard measures to compare data sets; and (14) experiencing all the phases of a data analysis investigation in which measuring is used to collect data. Seven student sheets are attached.