Systematic errors can cause measurements to deviate from the actual value of the quantity being measured. Faulty equipment (such as a meterstick that is not marked correctly), inaccurate calibration of measuring devices (such as a scale to measure mass that has not been properly zeroed), and improper use of equipment by the experimenter (such as misinterpreting the range of a voltmeter) are all examples of systematic errors. Some systematic errors are constant, whereas others are proportional to some quantity that changes in the experiment (whether that quantity is being measured or not). Systematic errors in a variety of laboratory exercises have been described in articles in "The Physics Teacher." (Contains 1 table and 3 figures.)