DPSCM 4155.18

DPSC STQP

l JUN 84

FOREWORD

(Supplementation is prohibited.)

DPSC Manual 4155.18 is published by the Defense 

Personnel Support Center for use by Government personnel assigned 

to inspection of items procured on DPSC subsistence contracts. 

Instructions are applicable to contractor personnel.

This Manual will be maintained in a current status and 

reviewed annually.

Users of this publication are encouraged to submit 

recommended changes and comments to improve the publication, 

through channels, to Directorate of Subsistence, ATTN: 

DPSC-STQP.

BY ORDER OF THE COMMANDER

PATRICIA FENWICK

Ch, Administrative Services Div

 Directorate of Installation Srv

DISTRIBUTION

 Special

ST-B thru ST-Q

DLA-IG and DLA-IGROs - 1 each

DPSC-IAA/Library - 2

DPSC-IO - 25

___________

This Manual supersedes DPSC Manual 4155.18, 1 Jul 78, and Change 

No. 1.

*Denotes Changes.
 DPSCM 4155.18

I. REFERENCES.

 A. $(SK) MILSTD105, Sampling Procedures and Tables for 

Inspection by Attributes.

 B. MILSTD109, Quality Assurance Terms and Definitions.

 C. MILHDBK53, Guide for Sampling Inspection.

 D. DPSC Manual 4155.5, Subsistence Contractor Inspection 

Procedures Manual.

 E. DPSC Manual 4155.6, Subsistence Inspection Manual.

II. PURPOSE AND SCOPE. The purpose of this Manual is to provide 

information regarding statistical sampling plans. This Manual is 

applicable to Government personnel performing inspection on DPSC 

subsistence contracts and may be used in briefing contractor's 

personnel on contractor inspection procedures.

III. DEFINITIONS.

 A. Major Total Defects Concept. This calls for assignment of 

separate Acceptable Quality Levels (AQLs) for each major class of 

defects and an AQL for the combined major and minor classes of 

defects. An AQL is not assigned to the minor class of defects, 

but the sampling plan for total defects pertains to the total of 

major defects plus minor defects found in the sample.

To standardize procedures and minimize confusion in using 

MILSTD105 to obtain a sampling plan (i.e. sample size, acceptance 

and rejection numbers) when a Table of Examination has more than 

one class of defects (e.g. major, minor, total) and a combination 

of AQLs, the inspector should follow the instructions in the 

applicable table of MILSTD105 to arrive at one sample size, with 

corresponding acceptance and rejection numbers, to be used for all 

classes of defects in the examination. When there are compelling 

reasons to use separate sample sizes for the different classes of 

defects, approval will be obtained from the quality assurance 

element of the contracting activity.

 B. Major-Minor Defects Concept. Such plans require separate 

AQLs for each class of defects, i.e., major and minor. This makes 

it possible for the sample size to vary for each class of defects. 

However, to minimize confusion and to facilitate application, it 

is preferable that the sample size be the same for all classes of 

defects in an examination, as for the major-total defects concept. 

This concept is currently being stressed in Military and Federal 

specifications more than the major total defects concept.
DPSCM 4155.18

IV. SAMPLING PLAN EXPRESSION OF NONCONFORMANCE.

 A. All sampling plans used by DPSC refer to MILSTD105 unless 

otherwise specified in the contract documents. They contain 

criteria for determining product acceptability or nonconformance 

as follows:

 1. "Defects per Hundred Units" (DHU or DPHU) expresses 

nonconformance based on the number of defects in the sample.

 2. "Percent Defective" (PD) expresses nonconformance based on 

the number of units in the sample that contain one or more 

defects.

 B. The elements of inspection, i.e., examination and testing, 

may use either term of expression of nonconformance in the 

sampling plans applied. 

V. TYPES OF SAMPLING PLANS.

 A. MILSTD105 is based on inspection by attributes, i.e., based 

on a characteristic either meeting or not meeting a requirement. 

Single, Double, Multiple, Reduced, Normal and Tightened Sampling 

Plans are provided. Tables XA thru XR of MILSTD105 depict 

approximate operating characteristic curves for the single 

sampling plans. Matching of the single sampling plan used to the 

corresponding operating characteristic curve provides an 

understanding of the producer and consumer risks associated with 

the particular single sampling plan. Producer risks are those 

associated with the rejection of lots of good quality, whereas 

consumer risks are those associated with the acceptance of lots of 

poor quality.

 1. "Single" sampling is ordinarily used because it provides 

the most information at least cost when quality is at or near the 

Acceptable Quality Level.

 2. Double or multiple sampling may be feasible when history 

records or observation of production at a plant show that quality 

is markedly worse or markedly better than the AQL.

 3. The type of sampling plan is omitted from Quality Assurance 

Provisions of contractual documents to permit flexibility in field 

inspection quality assurance operations.
DPSCM 4155.18

 B. Attribute sampling plans are identified as to severity of 

inspection, i.e., normal, tightened or reduced. The degree of 

inspection and the procedures for switching from one degree to 

another are explained in paragraph 8 of MILSTD105. In accordance 

with these procedures, MILSTD105, Tables I, IIA, IIIA, and IVA are 

used for normal inspection. Tables I, IIB, IIIB, and IVB are used 

for tightened inspection. Tables I, IIC, IIIC, and IVC are used 

for reduced inspection. This manual illustrates the extraction of 

sampling plans using normal inspection. The extraction of 

tightened or reduced sampling plans is performed in the same 

manner using the appropriate "B" or "C" series tables.

 C. Under the major total defects concept, the entire examination 

(all classes) will be subjected to tightened inspection when any 

one class in the examination qualifies for such inspection. Under 

the major minor defects concept only the affected class need be 

subjected to tightened inspection. Reduced inspection is 

discouraged due to the high risks associated with the reduced 

sampling plans.

 D. Lot Average and Composite Sampling Plans, based on a 

continuous scale of measurement of lot characteristic 

requirements, are also used by DPSC.

 1. Examples are net weight, net volume and milk fat content.

 2. These sampling plans may be effected in two ways:

 a. Lot Average Inspect each sample unit, record the 

individual results and compute the average. Compare this value 

with the average specification requirement to determine lot 

conformance.

 b. Composite Form a composite sample by intermingling and 

blending the individual units. (Equal portions from each unit may 

be used.) Inspect the composite sample and compare the results 

with the specification requirement.

 3. The contractual documents will indicate whether the lot 

average or composite sampling plan is to be used.
DPSCM 4155.18

VI. APPLICATION OF SAMPLING PLANS.

 A. General.

 1. The contract, or documents referenced in it, will specify 

the Inspection Levels and AQLs designating the sampling plans 

applicable to each element of inspection to be performed. For 

example, the contract may call for examination of primary 

containers, of net weight, and of product organoleptic qualities, 

and testing of physical and chemical properties of the product and 

component items.

 2. The factors for determining the sample sizes to be used for 

each examination or test are:

 a. The concept indicated, i.e., whether major total defects 

concept or major minor defects concept.

b. The Inspection Level.

c. The AQL.

d. The type of sampling plan utilized, i.e., single, double, 

or multiple.

 e. The severity of inspection required, i.e., normal, 

tightened or reduced.

 B. Example of Uses of Single Sampling Plans for Major Total 

Defects Concept under Normal Inspection.

This example involves single sampling of a lot of 3,250 

primary containers.

The specified inspection is Level II and AQLs are 0.15 DHU for 

Major A defects,

1.0 DHU for Major B defects, and 4.0 DHU for Total defects.

 a. Referring to MILSTD105, Table I, with the lot size of 

3,250 containers and Inspection Level II, we derive sample size 

code letter "L".

b. Referring code letter "L" to Table IIA of MILSTD105, we 

find that the corresponding sample size is 200 units (primary 

containers). Following this row horizontally to the right to 

determine the acceptance and rejection numbers associated with 

this sample size for the AQLs stipulated, we find an arrow 

pointing downward in the 0.15 AQL column, 5 and 6 respectively in 

the 1.0 AQL column, and 14 and 15 respectively in the 4.0 AQL 

column. Since these sampling plans use the major total defects 

concept, it is preferred that the sample size be increased to 315 

for all of the AQLs stipulated and not for just the Major A 

defects plan with an AQL of 0.15. Therefore, the proper sampling 

plans are:
DPSCM 4155.18

Sample Size Major A 

Major B Total

 AC RE AC 

RE AC RE

 3l5 l 2 7 

8 21 22

 c. Under the major total defects concept, the number of 

minor defects permitted is reduced by the number of major defects 

found. Therefore, if one defect of Major A class is found, only 

20 minor defects will be tolerated, provided no defects of Major B 

class are found without the lot being considered nonconforming. 

Similarly, the finding of any defects of Major B class reduces,

still further, the number of minor defects permitted. 

 C. Example of Use of Multiple Sampling Plans for Major Total 

Defects Concept under Normal Inspection.

This example involves sampling of a lot of 1,250 primary 

containers. The specified Inspection Level is II and AQLs are 

0.065 DHU for Major A defects, 1.0 DHU for Major B defects and 4.0 

for Total defects. (Sampling examinations of prior lots indicated 

that the quality was consistently better than the specified AQL 

and administrative decision permitted use of multiple sampling.)

a. Referring to MILSTD105, Table I, with lot size of 1,250 

units (containers) and Inspection Level II, we derive sample size 

code letter "K".

b. Referring code letter "K" to Table IVA of MILSTD105, we 

find a cumulative sample size of 224 units for seven increment 

sample sizes of 32 units each. Following these rows horizontally 

to the right, instead of criteria we find an arrow directing us 

downward in the 0.065 AQL column. Note, however, that the block 

below the arrow also lacks criteria for this next code letter "L". 

The asterisk in the block for code letter "L" and AQL of 0.065 

indicates use of the corresponding single sampling plan rather 

than the multiple sampling plan.
DPSCM 4155.18

c. Referring code letter "L" to Table IIA, we find the 

proper sampling plans are:

Sample Size Major A 

Major B Total

 AC RE 

AC RE AC RE

 200 0 1 

5 6 14 15

 d. When different sample sizes are indicated for the same 

examination or test in a lot, the entire amount of samples drawn 

for that inspection element ordinarily should not exceed the 

larger of the sample sizes. To facilitate the physical job of 

sampling, the larger sample should be drawn. As it is drawn, the 

lesser sample should be differentiated by marking and, if 

convenient, by physical separation from the units that bring the 

sample amount up to the size of the larger quantity. 

Differentiation should take place at the time the sample units are 

drawn, i.e., before any examination or testing is performed, to 

preclude bias in sampling. If examination or testing preceded 

differentiation, bias may be introduced intentionally or

inadvertently by redistributing defective units from the sequence 

of drawing. Such redistribution of defective units could result 

in a decision about conformance of the lot differing from what 

would properly have been indicated. When multiple sampling is to 

be used, consideration should be given to such factors as repeated 

availability of forklift equipment, repeated tearing down and 

rebuilding stacks of boxes, etc., as successive increment sample 

sizes may be required. Should these factors appear prohibitive as 

to time and effort, the entire cumulative sample size should be 

drawn from sufficient shipping containers in accordance with 

instruction as to number of units to be extracted per shipping 

container or case (e.g., not more than two units). The cases 

could then be opened as the need arose for successive increment 

sample sizes. Expansion of this general topic and examples 

follow.
DPSCM 4155.18

 e. In double or multiple sampling, differentiation of the 

increment sample size will be necessary for inspection in the 

proper sequence, if the indicated entire cumulative sample size is 

drawn; for example, the multiple sampling plans in Table IVA for 

code letter "G" and AQLs of 2.5 DHU for major defects and 10.0 DHU 

for total defects are:

 Cumulative

Sample Sample 

Major Total

Sample Size Size 

AQL 2.5 AQL 10.0

 

AC RE AC RE

First 8 8 

# 2 0 4

Second 8 16 

0 3 1 6

Third 8 24 

0 3 3 8

Fourth 8 32 

1 4 5 10

Fifth 8 40 

2 4 7 11

Sixth 8 48 

3 5 10 12

Seventh 8 56 

4 5 13 14

 

It should be noted that upon examination of the first sample size 

of eight units, a decision of nonconformance can be reached if two 

or more major defects, or four or more major and minor defects 

combined, or if both events occur. However, a decision of 

conformance cannot be reached before the second increment sample 

size has been inspected under this plan as the "#" means 

acceptance is not permitted at this sample size.
DPSCM 4155.18

 D. Single Sampling Plans: Major-Minor Defects Concept.

 1. Under the major-minor defects concept, more than one sample 

size per examination or testing may occur in both single sampling 

and double or multiple sampling. It is preferable to arrive at 

one sample size for all classes of defects in the examination (see 

paragraph VI.B.). Should compelling reasons exist for using a 

different sample size for each class of defects in the 

examination, the following means will be used to differentiate the 

various sample sizes.

 2. Single sampling for major minor concept entails drawing the 

large sample indicated by MILSTD105 and separating the smaller 

sample size either by marking or physical separation, or both, at 

the time the sample units are drawn. For example, Inspection 

Level S2 and AQLs of 1.5 DHU for major defects and 4.0 DHU for 

minor defects applied against a lot of 6,500 units indicates 

sample size code letter "D" in Table I. Referring to Table IIA 

with code letter "D", we find acceptance criteria associated with 

the corresponding sample size 8 for the AQL of 1.5 DHU and an 

arrow directing us downward to a larger sample size for the AQL of 

4.0 DHU. Therefore, the proper sampling plans are:

Class of Sample Acceptance Rejection

Defects Size No. No.

 Major 8 0 1

 Minor 13 1 2

Therefore, a maximum sample of 13 units should be drawn from the 

lot. The first randomly drawn units comprising the lesser sample 

size are differentiated by marking or tagging from the rest of the 

units that bring the total number up to the larger sample size. 

In this example, the lesser sample size (the first eight units 

drawn) shall be examined and the units scored for all classes of 

defects, i.e., majors and minors. The remaining units that 

complete the larger sample size (five in this example) shall be 

examined and the units scored for the applicable class of defects 

(minor defects in this example) only.

 
DPSCM 4155.18

 E. Multiple Sampling Plans: Major-Minor Defects Concept.

1. This circumstance requires more attention to the sequence 

in which the sample units are inspected for each class in order to 

comply with the randomness of selection. For example, Inspection 

Level I and AQLs of 1.0 DHU for major defects and 6.5 DHU for 

minor defects applied against a lot of 790 units indicates sample 

size code letter "G" in Table I. Referring to Table IVA with code 

letter "G", we find an arrow directing us downward to a larger 

sample size for the AQL of 1.0 DHU than for the sample sizes 

corresponding to code letter "G" for the AQL of 6.5 DHU. 

Therefore, the proper sampling plans are:

MAJOR DEFECTS MINOR DEFECTS

 Cumulative Cumulative

 Sample Sample Sample Sample

Sample Size Size AQL 1.0 Size Size 

AQL 6.5

 AC RE 

AC RE

First 13 13 # 2 8 8 

# 4

Second 13 26 # 2 8 16 

1 5

Third 13 39 0 2 8 24 

2 6

Fourth 13 52 0 3 8 32 

3 7

Fifth 13 65 1 3 8 40 

5 8

Sixth 13 78 1 3 8 48 

7 9

Seventh 13 91 2 3 8 56 

9 10

 2. To best illustrate the need for differentiation of the 

sample sizes for each class of defects and the sequence of 

inspection, the larger entire cumulative sample size will be drawn 

as indicated.
DPSCM 4155.18

Entire Cumulative Sample Size for Major Defects

1st 2nd 3rd 4th 5th 6th 7th

18 913 1416 1724 2526 2732 3339 40 4148 4952 5356 5765 6678 7991

1st 2nd 3rd 4th 5th 6th 7th

 Entire Cumulative Sample Size for Minor Defects

 

 3. Inspection should proceed as follows:

a. Examine units 1 through 8 for minor defects. If four or 

more minor defects are found, the lot is nonconforming and no 

further examination need be made for minor defects. If 0, 1, 2, 

or 3 minor defects are found, units 9 through 16 must be examined 

from the cumulative sample for minor defects.

 b. Examine units 1 through 13 for major defects. If two or 

more major defects are found, the lot is nonconforming and no 

further examination need be made for major defects. If 0 or 1 

major defect is found, units 14 through 26 must be examined from 

the cumulative sample size for major defects.

c. If examination of units 1 through 16 revealed 0 or 1 

minor defect, the lot is conforming for minor defects and no 

further examination for that class of defects need be made. 

Similarly, if not more than three minor defects were found in the 

first eight units and the cumulative sample of 16 units revealed 

five or more minor defects, the lot is nonconforming and no 

further examination for that class of defects need be made. If 2, 

3, or 4 minor defects were found in the cumulative sample of 16 

units, examination of units 17 through 24 must be made for minor 

defects.

d. If examination of units 1 through 26 revealed two or more 

major defects, the lot is nonconforming for major defects and no 

further examination for that class of defects need be made. If 0 

or 1 major defect is found in the 26 units examined thus far, 

units 27 through 39 must be examined for major defects. It should 

be noted that while a decision that the lot conforms for the minor 

defect class requires examining 16 units as a minimum; to reach 

the same decision for the major defects class requires examining 

39 units as a minimum.
DPSCM 4155.18

 4. The procedure for inspecting successive increment sample 

sizes is continued for any class until the number of defects for 

that class indicates nonconformance by equaling or exceeding the 

rejection number, or indicates conformance by being less than or 

equal to the acceptance number. Note that if 0 or 1 minor defect 

had been found in units 1 through 16, examination for major 

defects would continue through 39 units, at least, if less than 2 

major defects were found. Any minor defects found starting with 

unit 17 would not be scored or recorded since the lot had been 

found conforming to the criteria for the cumulative sample size 

for the second increment for minor defects. Similarly, if 0 major 

defects had been found in units 1 through 39 and examination for 

minor defects had to continue through unit 40, any major defects 

found starting with unit 40 would not be scored or recorded. The 

lot had been found conforming to the criteria for the cumulative 

sample size for the third increment for major defects. Scoring or 

recording defects of any particular class found after reaching a 

valid decision of conformance for that particular class on a 

previous sample size violates the doctrine of statistical 

sampling.

 

 5. Generally speaking, for each examination or test the 

entire single sample or first increment sample size of double or 

multiple sampling must be examined or tested. This is necessary 

in order to obtain a sufficiently accurate picture as to quality 

of the lot. Under certain conditions, however, it may not be 

desirable after the rejection number has been reached to complete 

inspection of the entire sample. When either of the conditions 

below apply, the inspection record will be annotated "Inspection 

stopped after...units because....". The blanks will be filled in, 

respectively, with the number of units and the reason for 

stopping, e.g., "moving lot inspection" or "improper nomenclature 

printed on cases." Conditions for halting inspection upon 

reaching the rejection number are:

a. When moving lot inspection is specified, the inspector 

will discontinue examination once the rejection number has been 

reached.
DPSCM 4155.18

b. When the defect is an overall or general defect, e.g., 

wrong markings printed on the shipping cases, wrong colored ink 

used for markings, cans not coated when coating is required, or 

vice versa, etc., that will appear in each unit in the lot, the 

inspector will discontinue each examination once the rejection 

number has been reached.

 F. Example of Double Sampling Plans: Major-Minor Defects 

Concept. This example involves sampling of a lot of 2,000 items. 

The specified Inspection Level is I and the AQLs are 1.0 DHU for 

major defects and 6.5 DHU for minor defects. A normal sampling 

plan is authorized.

a. Referring to MILSTD105, Table I, with lot size of 2,000 

items and Inspection Level I, sample size code letter "H" is 

derived.

b. From Table IIIA, sample size code letter "H" and AQLs of 

1.0 and 6.5, the following sampling plans are obtained.

 

 Cumulative AQL AQL

 Sample Size Sample Size 1.0 6.5

 AC RE AC RE

First 32 32 

0 2 3 7

Second 32 64 

1 2 8 9

c. From the first sample of 32 units, the lot is accepted if 

no major defects and if 3 or fewer minor defects are found. The 

lot is rejected if 2 or more major defects and/or if 7 or more 

minor defects are found. However, no decision can be made from 

the results of the first sample if 1 major defect and/or 4, 5 or 6 

minor defects are found. A second sample of 32 items must be 

taken. If the combined sample size of 64 items contains 1 or 

fewer major defects and 8 or fewer minor defects, the lot is 

accepted. If the combined sample size of 64 items contains 2 or 

more major defects and/or 9 or more minor defects the lot is 

nonconforming.

 
DPSCM 4155.18

d. The decision whether to draw the first sample, perform 

examination, and then draw the second sample if required, or 

whether to draw two samples before examination would depend on the 

particular circumstances involved (see paragraph VI.C.d.).

 G. Lot Average or Composite Sampling Plans. Lot average or 

composite sampling plans make use of MILSTD105 only for 

determining the sample size. These sampling plans call for other 

considerations before a decision is made on the lot acceptability 

when an apparent nonconformance is indicated by the results of the 

samples. Detailed information on lot average sampling plans is 

contained in DPSC Manual 4155.6. An example of determining the 

sample size from MILSTD105 for a lot average sampling plan would

be where the instructions read: "The sample size shall be the 

number of primary containers indicated by Inspection Level S1. 

Test requirements shall be lot average requirements." If the lot 

consisted of 24,000 primary containers of product, reference to 

Table I, MILSTD105, indicates code letter "C". Referring to Table 

IIA with code letter "C", we find the sample size to be 5 units. 

The MILSTD105 acceptance criteria, i.e., AQLs and Acceptance and 

Rejection Numbers, are not employed for lot average 

determinations.

 H. Lot Acceptance-Rejection Criteria. A lot shall be considered 

acceptable or conforming to requirements only if it passes every 

sampling plan applied. If the lot fails one or more sampling 

plans, it shall be considered unacceptable or nonconforming to 

requirements.

VII. INSTRUCTIONS FOR THE USE OF LIMITING QUALITY (LQ) VALUES.

 A. General.

 1. These values are applicable in those instances when it is 

desirable to control quality at particular consumer's risk (Pa) 

for isolated lots. When using MILSTD105 this is accomplished by 

the selection of a sampling plan that provides not less than a 

specified LQ protection and is associated with a designated AQL 

value. When the contractual documents stipulate an LQ value for 

a table of defects, the sampling plan shall be selected in 

accordance with the instructions of Section 11 of MILSTD105. 

This sampling plan shall be compared to the plan indicated by the 

Inspection Level and AQL without application of LQ information. 

The plan requiring the larger sample size will be used.
DPSCM 4155.18

 2. When LQs with the associated consumer's risk expressed as 

percent are used, they will be placed in contractual documents and 

will be identified as to Inspection Level and AQL to which they 

apply in any examination. An LQ value may be specified for one or 

more AQLs and for any examination or test.

 B. Sampling Plan - Limiting Quality Protection.

This example involves examination of a single lot 

(20,000 units) of ration component produced on contract. The 

following inspection data applies:

 

 AQLsLQs

Insp. Sample Lot Size

Level Unit Expressed as Major A Major B 

Total

 S2 Contents of Primary 0.65 2.5 

10.00

 Primary Container Container LQ = 8 DHU

 Pa = 10%

a. Refer to Table I, MILSTD105. For lot size of 20,000 with 

Inspection Level of S2, the sample size code letter indicated is 

"D".

b. Refer to Table IIA, MILSTD105, for code letter "D". In 

AQL column, headed 0.65, an arrow points downward resulting in the 

following sampling plan:

 DEFECTS

Sample Size Major A Major B Total

AC RE AC RE AC RE 20 

0 1 1 2 5 6

 c. Refer to Table VIB, MILSTD105. Contract specifies an LQ 

of 8 DHU. In AQL column, headed 0.65, locate the value, equal to 

or less than 8, which is "4.9". The sample size indicated is "80" 

and the code letter is "J".
DPSCM 4155.18

d. Refer to Table IIA, MILSTD105, for sampling plan for 

sample size code letter "J". Since the LQ sample size of 80 is 

greater than the sample size 20 indicated for code letter "D" 

(paragraph VII.B.b.), the following plan will apply:

 DEFECTS

Sample Size Major A Major B Total

AC RE AC RE AC RE 80 

1 2 5 6 14 15

e. In the above example, if the stipulated Inspection Level 

were "II" instead of "S2", Table I, MILSTD105, would have 

indicated the sample size code letter to be "M". Refer to Table 

IIA, MILSTD105, for code letter "M". An upward pointing arrow is 

encountered in the AQL column headed 10.0, which results in the 

following sampling plan:

 

 DEFECTS

Sample Size Major A Major B Total

AC RE AC RE AC RE 125 

2 3 7 8 21 22

f. The plan indicated by the LQ value would be the same as 

in paragraph VII.B.d. Since the sampling plan resulting from 

application of the LQ value has a smaller sample size and offers 

less protection than the sampling plan resulting from application 

of the Inspection Level and the AQL, the latter plan with the 

larger sample size is applied.

VIII. INSTRUCTIONS FOR COUNTING DEFECTIVES.

 A. This Manual has thus far discussed defects and methods of 

scoring defects. Some Quality Assurance Provisions are concerned 

with defective units rather than defects. Basically, a 

"defective" is a unit which contains one or more defects. A major 

defective is a unit containing one or more major defects; a minor 

defective is a unit containing one or more minor defects. 

Depending upon classification of defects, a unit may be scored 

simultaneously as a major defective and a minor defective, or 

simply as a defective.
DPSCM 4155.18

 B. There are two procedures for classifying defects:

 1. Procedure A: The Quality Assurance Provisions make no 

separation between majors and minors all defects are treated as a 

single class.

 2. Procedure B: The Quality Assurance Provisions separate 

major and minor defects they are counted separately.

 C. Counting: Procedure A. When all defects are treated as a 

single class, the first defect found is tallied as "1". Any 

subsequent defects in that same unit are tallied as "0". For 

example, in a shipping container the inspector finds three 

different defects. He records:

 1. Staples too far apart 1.

 2. Not properly glued 0.

 3. Ply separation 0.

 D. Upon completion of inspection of his sample size, he 

determines the quality of the lot by counting the tallied "1s". 

For example, if the sample contains 13 units, the following might 

illustrate results of examination of shipping containers.

Defects 

12 3 4 5 6 7 8 9 10 11 12 13

Ply Separation 1 1 1 1 1 

1 1 1

Not properly glued 0 0 1 0 

0 0

Staples too far apart 0 1 0 0 

1 

Marking illegible 0 0 0 

0 0 

Units numbered 6 and 12 contained no defects.

The total number of defects found is 24.

The total number of defectives found is 11.

NOTE: ( ) indicates no defect found for 

 that characteristic.
DPSCM 4155.18

 E. Counting: Procedure B.

 1. Major and minor defects are scored and counted separately 

when classified separately. The first major defect found on a 

unit is tallied "1"; the first minor defect found on a unit is 

tallied "1". If a major and a minor defect are found on the same 

unit, a "1" is tallied for major and a "1" is tallied for minor. 

Subsequent defects for either class of defects after the first 

defect is tallied as "0". Upon completion of inspection of his 

sample size, he determines the quality of the lot by counting the 

tallied "1s". For example:

Major Minor

Defect 103 10111

Defect 211 10

Defect 106 01

Defect 214 001

Defect 221 1

 2. The total number of major defects is 7; the total number of 

major defectives is 5.

 3. The total number of minor defects is 6; the total number of 

minor defectives is 3.