Item: Are you a hard hitter? systematic measurement error in the compression test
Title: Are you a hard hitter? systematic measurement error in the compression test
Proceedings: Proceedings of the 2006 International Snow Science Workshop, Telluride, Colorado
Authors: Spencer Logan, Colorado Avalanche Information Center, 325 Broadway WS#1, Boulder, CO 80305 USA, (303) 499-9650; firstname.lastname@example.org
Abstract: The compression test is an effective, internationally standardized stability test. One reason for the widespread use is that results are generally repeatable on adjacent tests, and results are similar between users. However, there is some error associated with any and every kind of measurement. Measurement error can be divided into two components, random error and systematic error. In the compression test, random error comes from spatial variations of snowpack properties, minor differences in test preparation, and other hard to control sources. Systematic error comes from differences in the way the tests are conducted, including how hard a tester taps. During this poster session I am collecting data about how the tapping technique for the compression test varies among avalanche professionals. This investigation will help answer the following questions: How variable are the taps of a single user? How much does impact force vary between users? How much does impact force increase between taps from the wrist and elbow? Taps from the elbow and shoulder? How do those increases differ between users? Are there significant differences in tapping technique? The experimental equipment consists of a force plate and video camera. Subjects tap on the force plate as they would on the shovel blade in a compression test. The force plate records the timing and impact force of the taps. A video camera records their hand motion. Video analysis will help determine how users' technique differs.
Keywords: compression test, stability tests, measurement error
Digital Abstract Not Available