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SWGDOG SC 9 - HUMAN SCENT DOGS 

Scent Identification Lineups 

Posted for Public Comment 9/2/2008 – 11/1/2008. Posted for Public Comment 1/19/2010 – 

3/19/2010. Approved by the membership 3/3/2010.

Scent identification lineups are canine examinations of human scent traces, in a comparative 

manner, in order to confirm the presence or absence of a match between objects or scent samples. 

See endnote1

. 

Statement of Purpose: To provide recommended best practice general guidelines for training, 

certification, and documentation pertaining to canines trained in conducting scent identification 

lineups. 

1. INITIAL TRAINING 

1.1. The handler training shall be conducted by a competent trainer from an entity that 

utilizes a structured curriculum with specific training and learning objectives to achieve 

scent identification. The handler’s training shall include the following topics: 

1.1.1. Human odor and factors influencing scent identification. 

1.1.2. Environmental conditions affecting odor dispersion. 

1.1.3. Proper handling, storage and disposition of objects used for pre-scenting the 

canine as required by the canine team’s department or agency. 

1.1.4. Proper techniques for evidence collection as required by the canine team’s 

department or agency. 

1.1.5. Proper collection, storage and disposition of lineup odor materials as required 

by the canine team’s department or agency. 

1.1.6. Proper preparation of the lineup according to the protocol required by the canine 

team’s department or agency. 

1.2. The canine training shall be conducted by a competent canine trainer from an entity that 

utilizes a structured curriculum with specific training and learning objectives. 

1.3. Initial training shall include sufficient obedience training to perform an effective and 

controlled search. 

1.4. The canine shall be trained to perform an effective and controlled search off-lead. 

1.5. The initial training of the canine shall include training of a determined specific response 

(active or passive alert). 

1.6. Initial training shall include odor for pre-scenting from a variety of objects typically 

expected in an operational setting, such as a handgun, tools, clothing et cetera. 
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1.7. The canine team’s training shall be continued until a level of operational proficiency is 

achieved and the team is certified. 

2. CANINE TEAM ASSESSMENTS 

2.1. Assessments are part of certification, maintenance training and proficiency testing. 

2.2. Each assessment is the evaluation of a search. 

2.3. The canine team shall be assessed in the following ways: 

2.3.1. Odor recognition assessments consist of the canine making four runs on two 

scent lineups. Each run is an attempt to match an odor sample to its matching 

lineup odor. These are called potential-match runs. 

2.3.1.1. Odor recognition assessments test the following: 

2.3.1.1.1. The ability of the canine to indicate matching human target 

odors in an array of different human distractor odors 

(lineup odors) after having been pre-scented on a target 

odor sample. 

2.3.1.1.2. The canine’s response. 

2.3.1.1.3. The handler’s interpretation of the canine’s alert. 

2.3.1.2. Preparation of lineup odor materials shall include the following steps: 

2.3.1.2.1. Odors from 12 different people shall be collected onto 

lineup odor materials prior to the assessment. 

2.3.1.2.2. The manner in which the material for the lineup is prepared 

shall be appropriate for the protocols of the agency and the 

training of the canine regarding material used to collect the 

scent, method and duration of contact time with odor and 

temporary storage of the scent samples. 

2.3.1.3. Preparation of pre-scenting materials shall include the following steps: 

2.3.1.3.1. The pre-scenting material from four different human targets 

shall be prepared prior to the assessment. 

 2.3.1.3.2. The pre-scenting material shall be collected and stored in 

the manner appropriate for the training of the canine: either 

objects that have been in direct contact with the people, or 

scent pads prepared from such objects. 

2.3.1.3.3. At least four different kinds of objects for pre-scenting 

(with respect to type of material) shall be used. The testing 

agency may define a list of such objects, e.g., screwdrivers, 

crowbars, hammers, gloves, caps. If pre-scenting is done on 

an object that has been in direct contact with a person, this 

object shall not be identical to the material used in the 

lineup. 

2.3.1.3.4. The objects shall vary in duration of contact time with the 

human target and method of contact within limits set by the 

testing agency. Examples include: handling a screwdriver 
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for three minutes, carrying a pair of gloves in a pocket for a 

day, and wearing a cap for an hour. 

2.3.1.3.5. The pre-scenting material shall be prepared either directly 

after, or at least 24 hours prior to the preparation of the 

lineup odors in order to prevent the transfer of the object 

material odor onto the lineup odors. 

2.3.1.4. Preparation of the lineups. 

2.3.1.4.1. Two six-position lineups consisting of odors from twelve 

different people shall be prepared prior to the assessment, 

in a manner consistent with the training of the canine and 

agency protocol. 

2.3.1.4.2. The two lineups shall be conducted at such time that the 

lineup material has aged in a manner appropriate for the 

training of the canine. 

2.3.1.5. Lineup protocol. 

2.3.1.5.1. The handler shall inform the assessor of the canine’s final 

response prior to the test. 

2.3.1.5.2 For each lineup, the canine team shall perform two runs 

with different scent matches within a time frame that is 

consistent with the training of the canine and the protocols 

of the agency. For each run, the handler shall be provided 

with an appropriate pre-scenting material chosen by the 

assessor. 

2.3.1.5.3. The handler shall not know the position of the matching 

lineup odor in any run. 

2.3.1.5.4. The handler interprets the canine response and 

communicates this outcome to the assessor. 

2.3.1.5.5. In the event of a correct match, the matching lineup odor 

shall be removed from the lineup. 

2.3.1.5.6. The assessor shall know the position of the matching odor 

in each run. 

2.3.1.5.7. In a successful outcome of a potential-match run, the 

canine alerts to the matching lineup odor and does not alert 

to any of the distractor lineup odors. 

2.3.1.5.8. The handler shall be informed if a run has been successful 

immediately after its conclusion. This allows the handler to 

reward a correct outcome appropriately. 

2.3.1.6. Evaluation: the canine shall conduct 75% of the runs successfully. 

2.3.2. Comprehensive assessment: should consist of six runs performed on three 

lineups. In four potential-match runs, an attempt is made to match an odor 

sample to its matching lineup odor. In two non-match runs, the canine team has 

to conclude the absence of a matching lineup odor to the odor sample presented. 

2.3.2.1. The comprehensive assessment tests the following: 

2.3.2.1.1. The ability of the canine to indicate matching human target 

odors in an array of different human distractor odors 
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(lineup odors) after having been pre-scented on a target 

odor sample in four potential-match runs. 

 2.3.2.1.2. The ability of the canine team to conclude the absence of a 

matching human target odor in an array of different human 

distractor odors after having been pre-scented on a target 

odor sample in two non-match runs. 

2.3.2.1.3. The canine’s response. 

2.3.2.1.4. The handler’s interpretation of canine’s response. 

2.3.2.1.5. The canine team should be tested on six different human 

target odors in three, two run lineups where each line up 

contains different human distractor odors. 

2.3.2.2. Preparation of lineup odor materials. 

2.3.2.2.1. Odors from at least eighteen different people shall be 

prepared prior to the assessment. These will be used in 

three lineups. 

2.3.2.2.2. The manner in which the material for the lineup is prepared 

shall be appropriate for the training level of the canine 

regarding the materials used to collect the scent, method 

and duration of contact time with odor and temporary 

storage of the scent samples. 

2.3.2.3. Preparation of pre-scenting materials. 

2.3.2.3.1. The pre-scenting material from the same eighteen different 

human targets and from at least two additional human 

targets shall be prepared prior to the assessment. 

2.3.2.3.2. The pre-scenting materials shall be collected and stored in 

the manner appropriate for the training of the canine: either 

objects that have been in direct contact with the people, or 

scent pads prepared from such objects. 

2.3.2.3.3. At least four different kinds of objects for pre-scenting 

(with respect to type of material) shall be used. The testing 

agency may define a list of such objects. If pre-scenting is 

done on an object that has been in direct contact with a 

person, this object shall not be identical to the material used 

in the lineup. 

2.3.2.3.4. The objects shall vary in age, duration of contact time with 

the human target and method of contact within limits set by 

the testing agency. 

2.3.2.3.5. The pre-scenting material shall be prepared either directly 

after, or at least 24 hours prior to the preparation of the 

lineup odors in order to prevent the transfer of object 

material odor onto the lineup odors. 

2.3.2.4. Preparation of the lineups. 

2.3.2.4.1 Three six-position lineups consisting of odors from 

eighteen different people shall be prepared in a manner 

consistent with the training of the canine prior to the 

assessment. 
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2.3.2.4.2 The three lineups shall be conducted at such a time that the 

lineup material has aged in a manner appropriate for the 

training of the canine. 

2.3.2.5. Lineup protocol. 

2.3.2.5.1. The handler shall inform the assessor of the canine’s final 

response prior to the test. 

2.3.2.5.2 For each lineup, the canine team shall perform two runs 

with different scent matches within a time frame that is 

consistent with the training of the canine and the protocols 

of the agency. For each run, the handler shall be provided 

with an appropriate pre-scenting material chosen by the 

assessor. 

 2.3.2.5.3. At least two runs chosen at random by the assessor shall be 

non-match runs and as such have no matching human target 

odor amidst the array of choices. 

2.3.2.5.4. For potential-match runs, the handler shall be provided 

with an appropriate pre-scenting material chosen at random 

by the assessor. 

2.3.2.5.5. For the non-match runs, the canine shall be pre-scented on 

material that does not have a matching lineup odor in any 

of the lineups. This material is pre-scented by the additional 

human targets described in 2.3.2.3. 

2.3.2.5.6. The handler shall not know the correct outcome of any run 

prior to the assessment. 

2.3.2.5.7. The handler interprets the canine response and 

communicates this outcome to the assessor. 

2.3.2.5.8. In the event of a correct match, the matching lineup odor 

shall be removed from the lineup. 

2.3.2.5.9. The assessor shall know the position of the matching odor 

in each run. 

2.3.2.5.10. A successful outcome of a potential-match run results when 

the canine alerts to the matching lineup odor and does not 

respond to any of the distractor lineup odors. This is called 

a correct positive. 

2.3.2.5.11. A successful outcome of a non-match run results when the 

canine does not alert to any of the distractor lineup odors. 

This is called a correct negative. 

2.3.2.5.12. The handler shall be informed if a run has been successful 

immediately after its conclusion. This allows the handler to 

reward the canine for a correct outcome appropriately. 

2.3.2.6. Evaluation: The canine shall conduct 75 % of the runs correctly, and 

not make a false alert (false positive) to any of the distractor lineup 

odors in any of the runs. A single non-alert (miss) is therefore 

permissible. 

2.3.3. Double-blind assessment. 
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2.3.3.1. A double-blind assessment should consist of one or more lineups 

conducted according to the team’s usual protocol, including a realistic 

scent trace for pre-scenting the dog. 

2.3.3.2. Preparation of lineup odor material. 

2.3.3.2.1. The odors of the control target, the assessment suspect 

target and the distractor targets shall be prepared prior to 

the lineup. 

2.3.3.2.2. The manner in which the material for the lineup is prepared 

shall be appropriate for the training of the canine in terms 

of material used to collect the scent, method and duration 

of contact time with odor, odor collection, and temporary 

storage of the scent samples. 

2.3.3.3. Preparation of the pre-scenting material. 

2.3.3.3.1. For the control runs in the lineup, the material for prescenting shall be prepared in accordance to the usual 

protocol. 

2.3.3.3.2. For the realistic scent trace, the material for pre-scenting 

shall be prepared prior to preparation of the lineup material. 

2.3.3.3.3. The odor samples for pre-scenting shall be collected and 

stored in the manner appropriate for the training of the 

canine: either objects that have been in direct contact with 

the people, or scent pads prepared from such objects. 

2.3.3.3.4. The objects shall vary in age, duration of contact time with 

the human target and method of contact to mimic 

operational variation. 

2.3.3.4. Preparation of the lineups. 

2.3.3.4.1. The lineup shall be prepared in a manner consistent with 

the training of the canine. 

2.3.3.4.2. The lineup shall be conducted at such time that the lineup 

material has aged in a manner appropriate for the training 

of the canine. 

2.3.3.5. Lineup protocol. 

2.3.3.5.1. The lineup shall be conducted according to the protocol 

determined by the agency for which the team is working. 

2.3.3.6. Evaluation. 

2.3.3.6.1. No one present in the room, including the dog and handler 

shall know the correct outcome of the lineup. 

2.3.3.6.2. At the conclusion of each assessment run, the handler may 

be notified immediately of the outcome in a manner that 

does not compromise the integrity of the double-blind test. 

3. CANINE TEAM CERTIFICATION 

3.1. Certification for the named canine team shall be valid for one year. 
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3.1.1. Certification does not relieve the canine team from regular maintenance training, 

periodic proficiency assessments, and following other recommended SWGDOG 

guidelines. 

3.1.2. The certifying officials shall not be routinely involved in the day to day training 

of the canine team being evaluated. 

3.1.3. Handler errors, when excessive, may result in the failure of the team. 

3.2. Certification shall consist of a number of lineups that together form the full test. 

3.2.1. Human odors (both target and distractor) used in the day to day training of the 

team being certified shall not be used in the certification process. 

3.2.2. Lineup material and material used for pre-scenting the canine shall not have 

been used for another dog prior to being used in certification. 

3.2.3. The certification shall be comprised of a comprehensive assessment which 

incorporates odor recognition to such an extent that a separate odor recognition 

test is not necessary. The comprehensive assessment may be combined with a 

double-blind assessment. 

3.3. A canine team that fails the certification process shall complete a corrective action plan 

before making another attempt to certify. 

4. MAINTENANCE TRAINING 

4.1. The canine team shall conduct regular objective-oriented training sufficient to maintain 

and enhance operational proficiency. Maintenance training shall include the following: 

4.1.1. A variety of objects (varying shapes, sizes, manner and duration of contact, 

weights, materials, etc.) used for pre-scenting, or for the collection of scent for 

pre-scenting. 

4.1.2. A variety of human targets and distractors. 

4.1.3. A variety of durations of set times and environmental conditions during this set 

time for the objects used for pre-scenting. 

4.1.4. A varied duration of storage of objects used for pre-scenting. 

4.2. Training conducted solely by the handler to maintain the canine’s proficiency is 

acceptable, but should be regularly combined with assisted training in order to conduct 

single-blind training exercises. 

4.3. Supervised training should be conducted periodically. 

4.3.1. Supervised training, by a qualified trainer or instructor, is recommended in 

order to monitor and improve performance, identify and correct training 

deficiencies, and to perform proficiency assessments. 

4.4. Scent identification training shall be conducted at least 16 hours per month to maintain 

and improve the proficiency level of the team. Training should be distributed evenly 

throughout the month. 
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4.5. The canine team shall undergo periodic proficiency assessments as outlined in section 2 

- the Canine Team Assessments. These assessments should include a variety of odor 

recognition assessments, comprehensive assessments and double-blind assessments. 

5. RECORDS AND DOCUMENT MANAGEMENT 

5.1. The handler and department or organization shall document training, certification, 

proficiency assessments and deployment data. 

5.1.1. Training and proficiency assessment records may be combined or maintained 

separately. 

5.1.2. Deployment records shall be maintained separately from training, certification 

and proficiency assessment records. 

5.1.3. Training records should be standardized within the department or organization. 

5.2. Training records may include, but are not limited to, the following data: 

5.2.1. Name of handler and canine. 

5.2.2. Names of individuals conducting or assisting with the training. 

5.2.3. Time and date training took place. 

5.2.4. Location and environmental conditions. 

5.2.5. Training design (non-blind, single-blind or double-blind). 

5.2.6. Names or descriptions of individuals contributing odor to the lineup. 

5.2.7. Detailed descriptions of articles used for pre-scenting (duration of contact, 

method of preparation and storage, type of article, etc.). 

5.2.8. Results. 

5.2.9. Deficiencies and corrective measures implemented. 

5.3. Certification records shall be maintained by the certifying authority and the handler and 

include the following information: 

5.3.1. Name of handler and canine. 

5.3.2. Date team certified. 

5.3.3. Certification authority, i.e., agency, professional organization, or individuals. 

5.3.4. The standard or guideline under which the canine team is certified. 

5.3.5. Names of individuals awarding certification. 

5.3.6. Location of certification. 

5.3.7. A complete description of certification tests in accordance with section 2. 

5.4. Proficiency assessment records maintained by the handler and department or 

organization may include, but are not limited to, the following data: 

5.4.1. Name of handler and canine. 

5.4.2. Names of individuals conducting assessment. 

5.4.3. Time and date assessment took place. 

5.4.4. Location and environmental conditions. 

5.4.5. Assessment design (single-blind or double-blind). 

5.4.6. Names of individuals contributing odor to the lineup. 
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5.4.7. Detailed description of the article used for pre-scenting (duration of contact and 

method of preparation and storage, type of article, etc). 

5.4.8. Results. 

5.5. Supervisory review of all records is recommended. 

5.6. Digitally formatted records are recommended to facilitate compiling and analyzing data. 

5.7. Records may be discoverable in court proceedings and may become evidence of the 

canine team’s reliability. Record retention policy shall be determined by department or 

organization guidelines. 

5.8. Training records are necessary to illustrate the type and amount of training that the 

team has experienced before and after certification. 

5.9. Confirmed operational outcomes can be used as a factor in determining capability. 

5.10. Unconfirmed operational outcomes shall not be used as a factor in determining 

capability in that they do not correctly evaluate a canine team’s proficiency. 

5.11. Veterinary records. 

5.11.1. Veterinary records shall be maintained in a manner such as they are accessible 

to the handler/department/organization. 

5.11.2. Vaccinations required by state or local law should be documented in the 

veterinary record of the canine. 

 

 

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 Scent identification lineups are primarily used in criminal investigations. These lineups can 

assist investigators in identifying or eliminating suspects in cases where human scent has been 

collected as evidence. Highly trained canines conduct scent identification lineups according to a 

set of strictly administered protocols. Protocols address topics such as: 

 Human scent evidence collection, preservation and storage. 

 Lineup material preparation. 

 Scent identification lineup preparation of both control and target lineup. 

 Lineup protocols. 

 Department/agency specific procedures.