ASTM C670-03

Standard Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials

ABSTRACT
This practice provides guidance in preparing precision and bias statements for ASTM test methods pertaining to construction materials. Test method shall conform to the maximum acceptable range of individual measurements. In order to be valid the indexes of precision to be included in the precision statement as guides for the operator must be based on estimates of the precision of the test method obtained from a statistically designed inter-laboratory series of tests. This series of tests must involve a sufficient number of laboratories, materials, and replicate measurements so that the results obtained provide reliable estimates of the true precision characteristic of the test method. The procedures described in this practice are based on the assumption that the proper estimates of precision have already been obtained. In any test method, tolerances are placed on the accuracy of measuring equipment. All tests made with a given set of equipment which has an error within the permitted tolerance will produce results with a small consistent bias, but that bias is not inherent in the test method and is not included in the bias statement for the test method. There are two conditions which permit the bias of a test method to be estimated: a standard reference sample of known value has been tested by the test method, and the test method has been applied to a sample which has been compounded in such a manner that the true value of the property being measured is known, such as may be the case, for example, in a test for cement content of concrete.
SCOPE
1.1 This practice supplements Practice E 177, in order to provide guidance in preparing precision and bias statements for ASTM test methods pertaining to certain construction materials (Note 0). Recommended forms for precision and bias statements are included. A discussion of the purpose and significance of these statements for the users of those test methods is also provided.
Note 1—Although under the jurisdiction of Committee C-9, this practice was developed jointly by Committees C-1, D-4, and C-9, and has been endorsed by all three committees. It has subsequently been adopted for use by Committee D-18.

General Information

• Status: Historical
• Publication Date: 09-Jan-2003
• ICS: 91.100.01 - Construction materials in general
• Technical Committee: C09 - Concrete and Concrete Aggregates
• Drafting Committee: C09.94 - Evaluation of Data (Joint C09 and C01)

Relations

• Replaces: ASTM C670-96 - Standard Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
• Effective Date: 10-Jan-2003
• Replaced By: ASTM C670-10 - Standard Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
• Effective Date: 01-Oct-2010
• Referred By: ASTM C1356-07(2020) - Standard Test Method for Quantitative Determination of Phases in Portland Cement Clinker by Microscopical Point-Count Procedure
• Effective Date: 10-Jan-2003
• Referred By: ASTM D546-17 - Standard Test Method for Sieve Analysis of Mineral Filler for Asphalt Paving Mixtures
• Effective Date: 10-Jan-2003
• Referred By: ASTM C136/C136M-19 - Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates
• Effective Date: 10-Jan-2003
• Referred By: ASTM C805/C805M-18 - Standard Test Method for Rebound Number of Hardened Concrete
• Effective Date: 10-Jan-2003
• Referred By: ASTM D1883-21 - Standard Test Method for California Bearing Ratio (CBR) of Laboratory-Compacted Soils
• Effective Date: 10-Jan-2003
• Referred By: ASTM D5581-07A(2021)e1 - Standard Test Method for Resistance to Plastic Flow of Bituminous Mixtures Using Marshall Apparatus (6 in. Diameter Specimen)
• Effective Date: 10-Jan-2003
• Referred By: ASTM C188-17(2023) - Standard Test Method for Density of Hydraulic Cement
• Effective Date: 10-Jan-2003
• Referred By: ASTM C1608-17 - Standard Test Method for Chemical Shrinkage of Hydraulic Cement Paste
• Effective Date: 10-Jan-2003
• Referred By: ASTM C593-19 - Standard Specification for Fly Ash and Other Pozzolans for Use With Lime for Soil Stabilization
• Effective Date: 10-Jan-2003
• Referred By: ASTM C918/C918M-20 - Standard Test Method for Measuring Early-Age Compressive Strength and Projecting Later-Age Strength
• Effective Date: 10-Jan-2003
• Referred By: ASTM D7370/D7370M-14(2021) - Standard Test Method for Determination of Relative Density and Absorption of Fine, Coarse, and Blended Aggregate Using Combined Vacuum Saturation and Rapid Submersion
• Effective Date: 10-Jan-2003
• Referred By: ASTM C513/C513M-11(2019) - Standard Test Method for Obtaining and Testing Specimens of Hardened Lightweight Insulating Concrete for Compressive Strength
• Effective Date: 10-Jan-2003
• Referred By: ASTM C1427-21 - Standard Specification for Extruded Preformed Flexible Cellular Polyolefin Thermal Insulation in Sheet and Tubular Form
• Effective Date: 10-Jan-2003

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:C670–03
Standard Practice for
Preparing Precision and Bias Statements for Test Methods
1
for Construction Materials
This standard is issued under the fixed designation C670; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope* estimateofthestandarddeviationorsigmathatischaracteristic
of the total statistical population. The one-sigma limit is an
1.1 This practice supplements Practice E177, in order to
indication of the variability (as measured by the deviations
provideguidanceinpreparingprecisionandbiasstatementsfor
above and below the average) of a large group of individual
ASTM test methods pertaining to certain construction materi-
test results obtained under similar conditions.
als (Note 1). Recommended forms for precision and bias
3.2.1 single-operator one-sigma limit—the one-sigma limit
statements are included. A discussion of the purpose and
for single-operator precision is a quantitative estimate of the
significance of these statements for the users of those test
variability of a large group of individual test results when the
methods is also provided.
testshavebeenmadeonthesamematerialbyasingleoperator
NOTE 1—Although under the jurisdiction of Committee C-9, this
using the same apparatus in the same laboratory over a
practice was developed jointly by Committees C-1, D-4, and C-9, and has
relatively short period of time. This statistic is the basic one
been endorsed by all three committees. It has subsequently been adopted
usedtocalculatethesingle-operatorindexofprecisiongivenin
for use by Committee D-18.
the precision statement for guidance of the operator.
2. Referenced Documents 3.2.2 multilaboratory one-sigma limit—the one-sigma limit
2
for multilaboratory precision is a quantitative estimate of the
2.1 ASTM Standards:
variability of a large group of individual test results when each
C109/C109M Test Method for Compressive Strength of
testhasbeenmadeinadifferentlaboratoryandeveryefforthas
Hydraulic Cement Mortars (Using 2-in. or [50-mm] Cube
been made to make the test portions of the material as nearly
Specimens)
identical as possible. Under normal circumstances the esti-
C802 Practice for Conducting an Interlaboratory Test Pro-
mates of one-sigma limit for multilaboratory precision are
gram to Determine the Precision of Test Methods for
larger than those for single-operator precision, because differ-
Construction Materials
entoperatorsanddifferentapparatusarebeingusedindifferent
E177 Practice for Use of the Terms Precision and Bias in
laboratories for which the environment may be different.
ASTM Test Methods
3.2.3 one-sigma limit in percent (1s%)—in some cases the
3. Terminology
coefficient of variation is used in place of the standard
deviation as the fundamental statistic. This statistic is termed
3.1 Definitions of Terms Specific to This Standard:
the“one-sigmalimitinpercent”(abbreviated(1s%))andisthe
3.2 one-sigma limit (1s)—the fundamental statistic underly-
appropriate standard deviation (1s) divided by the average of
ing all indexes of precision is the standard deviation of the
the measurements and expressed as a percent. When it is
population of measurements characteristic of the test method
appropriatetouse(1s%)inplaceof(1s)isdiscussedinSection
when the latter is applied under specifically prescribed condi-
6.
tions (a given system of causes). The terminology “one-sigma
3.3 Acceptable Range of Results:
limit” (abbreviated (1s)) is used in Practice E177 to denote the
3.3.1 acceptable difference between two results—the “dif-
ference two-sigma limit (d2s)” or “difference two-sigma limit
1
This practice is under the jurisdiction of ASTM Committee C09 on Concrete
in percent (d2s%),” as defined in Practice E177, has been
and Concrete Aggregates and is the direct responsibility of Subcommittee C09.94
selectedastheappropriateindexofprecisioninmostprecision
on Evaluation of Data.
statements. These indexes indicate a maximum acceptable
Current edition approved Jan. 10, 2003. Published March 2003. Originally
approved in 1971. Last previous edition approved in 1996 as C670-96. DOI:
difference between two results obtained on test portions of the
10.1520/C0670-03.
same material under the applicable system of causes described
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
in 4.1.1 and 4.1.2 (or whatever other system of causes is
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page
...