The guidelines presented in this practice for retaining significant digits and rounding numbers may be adopted by the using agency or user. Generally, their adoption should be used for calculating and recording data when specified requirements are not included in a standard.

The guidelines presented herein should not be interpreted as absolute rules but as guides to calculate and report observed or test data without exaggerating or degrading the accuracy of the values.

4.2.1 The guidelines presented emphasize recording data to enough significant digits or number of decimal places to allow sensitivity and variability analyses to be performed, see 3.2.

1.1 This practice is intended to promote uniformity in recording significant digits for measured and calculated values involving geotechnical data. The guidelines presented are industry standard, and are representative of the significant digits that should generally be retained. The guidelines do not consider material variation, purpose for obtaining the data, special purpose studies, or any considerations for the user's objectives; and it is common practice to increase or reduce significant digits of reported data to be commensurate with these considerations. It is beyond the scope of this practice to consider significant digits used in analysis methods for engineering design..

1.1.1 Using significant digits in geotechnical data involves the processes of collecting, calculating, and recording either measured values or calculated values (results), or both.

1.2 This practice accepts a variation of the traditional rounding method that recognizes the algorithm common to most hand-held calculators, see . The traditional rounding method (see ) is in accordance with Practice E 29 or IEEE/ASTM SI 10.

1.3 This practice offers a set of instructions for performing one or more specific operations. This document cannot replace education or experience and should be used in conjunction with professional judgment. Not all aspects of this practice may be applicable in all circumstances. This ASTM standard is not intended to represent or replace the standard of care by which the adequacy of a given professional service must be judged, nor should this document be applied without consideration of a project's many unique aspects. The word "Standard" in the title of this document means only that the document has been approved through the ASTM consensus process.