Trial Outcomes & Findings for Prevention of Paralytic Shellfish Poisoning in Subsistence Shellfish Harvest Communities of Southeast Alaska (NCT NCT05247229)
NCT ID: NCT05247229
Last Updated: 2025-10-03
Results Overview
The investigators will assess student learning with pre-unit and post-unit written evaluations that collect information on students' cultural and scientific knowledge using Likert scale questions. Likert-scale responses ranged from disagree (1) to agree (5). Here we report post education unit outcomes. We report pre education unit outcomes in baseline characteristics. Questions 10 and 13 of our survey reflect this outcome measure.
COMPLETED
NA
50 participants
The time frame is one educational semester, lasting 10 weeks (10 units administered weekly). Here we report post education unit outcomes (following the semester-long program). We report pre education program outcomes in baseline characteristics.
2025-10-03
Participant Flow
All participants who enrolled in the study completed the study.
Participant milestones
| Measure |
Middle School Education Program
The education intervention centers around teaching children about local traditional ecological knowledge and traditional harvesting and gathering practices, including those for shellfish.
The education program is divided into three units, following other tribal education programs. Primary data collection will be conducted by unit to assess student learning for each unit. The first unit will cover an introduction to shellfish, harmful algal blooms (HAB), and paralytic shellfish poisoning (PSP). The second unit will cover herring and how herring relates to Tlingit culture. The third unit will focus on intertidal zones as zones relate to Tlingit culture.
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|---|---|
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Overall Study
STARTED
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50
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Overall Study
COMPLETED
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50
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Overall Study
NOT COMPLETED
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0
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Reasons for withdrawal
Withdrawal data not reported
Baseline Characteristics
Differences between the participant numbers in the rows and the overall numbers are due to participant non-response.
Baseline characteristics by cohort
| Measure |
Middle School Education Program
n=50 Participants
The education intervention centers around teaching children about local traditional ecological knowledge and traditional harvesting and gathering practices, including those for shellfish.
The education program is divided into three units, following other tribal education programs. Primary data collection will be conducted by unit to assess student learning for each unit. The first unit will cover an introduction to shellfish, harmful algal blooms (HAB), and paralytic shellfish poisoning (PSP). The second unit will cover herring and how herring relates to Tlingit culture. The third unit will focus on intertidal zones as zones relate to Tlingit culture.
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|---|---|
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Age, Continuous
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12.6 years
n=50 Participants
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Sex/Gender, Customized
Male
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21 Participants
n=50 Participants
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Sex/Gender, Customized
Female
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18 Participants
n=50 Participants
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|
Sex/Gender, Customized
Nonbinary
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5 Participants
n=50 Participants
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Sex/Gender, Customized
Questioning
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1 Participants
n=50 Participants
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Sex/Gender, Customized
Not reported
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5 Participants
n=50 Participants
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|
Race (NIH/OMB)
American Indian or Alaska Native
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7 Participants
n=50 Participants
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Race (NIH/OMB)
Asian
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0 Participants
n=50 Participants
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Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
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1 Participants
n=50 Participants
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Race (NIH/OMB)
Black or African American
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0 Participants
n=50 Participants
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Race (NIH/OMB)
White
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9 Participants
n=50 Participants
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Race (NIH/OMB)
More than one race
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25 Participants
n=50 Participants
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Race (NIH/OMB)
Unknown or Not Reported
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8 Participants
n=50 Participants
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Ethnicity (NIH/OMB)
Hispanic or Latino
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1 Participants
n=50 Participants
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Ethnicity (NIH/OMB)
Not Hispanic or Latino
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46 Participants
n=50 Participants
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Ethnicity (NIH/OMB)
Unknown or Not Reported
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3 Participants
n=50 Participants
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Pre-program survey responses
1: Subsistence clam harvesting is enjoyable
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3.6 Scores on a scale
STANDARD_DEVIATION 0.9 • n=39 Participants • Differences between the participant numbers in the rows and the overall numbers are due to participant non-response.
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Pre-program survey responses
2: Subsistence clam harvesting is rewarding
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4.1 Scores on a scale
STANDARD_DEVIATION 1.0 • n=39 Participants • Differences between the participant numbers in the rows and the overall numbers are due to participant non-response.
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Pre-program survey responses
3: People I care about approve of clam harvest
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4.3 Scores on a scale
STANDARD_DEVIATION 1.0 • n=43 Participants • Differences between the participant numbers in the rows and the overall numbers are due to participant non-response.
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Pre-program survey responses
4: Peers participate in clam harvesting
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3.1 Scores on a scale
STANDARD_DEVIATION 1.2 • n=43 Participants • Differences between the participant numbers in the rows and the overall numbers are due to participant non-response.
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Pre-program survey responses
5: Whether I harvest is up to me
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4.2 Scores on a scale
STANDARD_DEVIATION 1.2 • n=43 Participants • Differences between the participant numbers in the rows and the overall numbers are due to participant non-response.
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Pre-program survey responses
6: I intend to clam harvest this year
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4.0 Scores on a scale
STANDARD_DEVIATION 1.3 • n=43 Participants • Differences between the participant numbers in the rows and the overall numbers are due to participant non-response.
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Pre-program survey responses
7: I have participated in clam harvesting
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2.5 Scores on a scale
STANDARD_DEVIATION 1.8 • n=42 Participants • Differences between the participant numbers in the rows and the overall numbers are due to participant non-response.
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Pre-program survey responses
9: Checking website before clamming is rewarding
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3.5 Scores on a scale
STANDARD_DEVIATION 1.3 • n=37 Participants • Differences between the participant numbers in the rows and the overall numbers are due to participant non-response.
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Pre-program survey responses
10: Checking website before clamming is easy
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3.8 Scores on a scale
STANDARD_DEVIATION 1.2 • n=37 Participants • Differences between the participant numbers in the rows and the overall numbers are due to participant non-response.
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Pre-program survey responses
11: Those I get clams with approve of check site
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3.9 Scores on a scale
STANDARD_DEVIATION 1.2 • n=35 Participants • Differences between the participant numbers in the rows and the overall numbers are due to participant non-response.
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Pre-program survey responses
12: People like me will check website before clam
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3.2 Scores on a scale
STANDARD_DEVIATION 1.3 • n=37 Participants • Differences between the participant numbers in the rows and the overall numbers are due to participant non-response.
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Pre-program survey responses
13: I am confident I can check website before clam
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3.6 Scores on a scale
STANDARD_DEVIATION 1.2 • n=38 Participants • Differences between the participant numbers in the rows and the overall numbers are due to participant non-response.
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Pre-program survey responses
14: Checking website is up to me
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4.0 Scores on a scale
STANDARD_DEVIATION 1.2 • n=38 Participants • Differences between the participant numbers in the rows and the overall numbers are due to participant non-response.
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Pre-program survey responses
15: I intend to check website to decide to clam
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3.8 Scores on a scale
STANDARD_DEVIATION 1.2 • n=38 Participants • Differences between the participant numbers in the rows and the overall numbers are due to participant non-response.
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Pre-program interview themes
Some/ high knowledge of PSP
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15 Participants
n=37 Participants • Differences between the participant numbers in the rows and the overall numbers are due to 37 total pre-program interviews being conducted with participants.
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Pre-program interview themes
Some/ high knowledge of risk reduction strategies
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8 Participants
n=37 Participants • Differences between the participant numbers in the rows and the overall numbers are due to 37 total pre-program interviews being conducted with participants.
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Pre-program interview themes
Some/ high knowledge of SEATOR resources
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3 Participants
n=37 Participants • Differences between the participant numbers in the rows and the overall numbers are due to 37 total pre-program interviews being conducted with participants.
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PRIMARY outcome
Timeframe: The time frame is one educational semester, lasting 10 weeks (10 units administered weekly). Here we report post education unit outcomes (following the semester-long program). We report pre education program outcomes in baseline characteristics.Population: Differences between the population numbers in the rows and the overall numbers are due to participant non-response.
The investigators will assess student learning with pre-unit and post-unit written evaluations that collect information on students' cultural and scientific knowledge using Likert scale questions. Likert-scale responses ranged from disagree (1) to agree (5). Here we report post education unit outcomes. We report pre education unit outcomes in baseline characteristics. Questions 10 and 13 of our survey reflect this outcome measure.
Outcome measures
| Measure |
Middle School Education Program
n=50 Participants
The education intervention centers around teaching children about local traditional ecological knowledge and traditional harvesting and gathering practices, including those for shellfish.
The education program is divided into three units, following other tribal education programs. Primary data collection will be conducted by unit to assess student learning for each unit. The first unit will cover an introduction to shellfish, harmful algal blooms (HAB), and paralytic shellfish poisoning (PSP). The second unit will cover herring and how herring relates to Tlingit culture. The third unit will focus on intertidal zones as zones relate to Tlingit culture.
|
|---|---|
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Student Assessment Questionnaire of Student Learning From Each Educational Unit.
10: Checking website before clamming is easy
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4.2 Scores on a scale
Standard Deviation 0.9
|
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Student Assessment Questionnaire of Student Learning From Each Educational Unit.
13: I am confident I can check website before clam
|
3.9 Scores on a scale
Standard Deviation 1.3
|
PRIMARY outcome
Timeframe: The time frame is one educational semester, lasting 10 weeks (10 units administered weekly). Here we report post education unit outcomes (following the semester-long program). We report pre education program outcomes in baseline characteristics.Population: Differences between the population numbers in the rows and the overall numbers are due to participant non-response.
The investigators will assess changes in student self-reported behavioral history and student behavioral intentions with pre-unit and post-unit written evaluations that collect information on students' history to date of participating in subsistence shellfish harvest activities and students' behavioral intentions to participate in subsistence shellfish harvest activities and to check the SEATOR website, measured using Likert scale questions. Likert-scale responses ranged from disagree (1) to agree (5). Here we report post education unit outcomes. We report pre education unit outcomes in baseline characteristics. Questions 6, 7, 8, 15, and 16 reflect this outcome measure. Questions 8 and 16 are excluded from the pre-post program statistical tests as these questions are only relevant in the post-program survey.
Outcome measures
| Measure |
Middle School Education Program
n=50 Participants
The education intervention centers around teaching children about local traditional ecological knowledge and traditional harvesting and gathering practices, including those for shellfish.
The education program is divided into three units, following other tribal education programs. Primary data collection will be conducted by unit to assess student learning for each unit. The first unit will cover an introduction to shellfish, harmful algal blooms (HAB), and paralytic shellfish poisoning (PSP). The second unit will cover herring and how herring relates to Tlingit culture. The third unit will focus on intertidal zones as zones relate to Tlingit culture.
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|---|---|
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Student Assessment Questionnaire of Student Behaviors and Behavioral Intentions Related to Shellfish Consumption and Checking SEATOR Website (Accessing a Tribal Resource to Prevent Poisoning).
7: I have participated in clam harvesting
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2.8 Scores on a scale
Standard Deviation 1.8
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Student Assessment Questionnaire of Student Behaviors and Behavioral Intentions Related to Shellfish Consumption and Checking SEATOR Website (Accessing a Tribal Resource to Prevent Poisoning).
8: Learning clam safety I am more willing to clam
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4.4 Scores on a scale
Standard Deviation 0.9
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Student Assessment Questionnaire of Student Behaviors and Behavioral Intentions Related to Shellfish Consumption and Checking SEATOR Website (Accessing a Tribal Resource to Prevent Poisoning).
15: I intend to check website to decide to clam
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3.9 Scores on a scale
Standard Deviation 1.0
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Student Assessment Questionnaire of Student Behaviors and Behavioral Intentions Related to Shellfish Consumption and Checking SEATOR Website (Accessing a Tribal Resource to Prevent Poisoning).
16: I have used website to inform decision to clam
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3.1 Scores on a scale
Standard Deviation 1.5
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Student Assessment Questionnaire of Student Behaviors and Behavioral Intentions Related to Shellfish Consumption and Checking SEATOR Website (Accessing a Tribal Resource to Prevent Poisoning).
6: I intend to clam harvest this year
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3.4 Scores on a scale
Standard Deviation 1.4
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PRIMARY outcome
Timeframe: The time frame is one educational semester, lasting 10 weeks (10 units administered weekly). Here we report post education unit outcomes (following the semester-long program). We report pre education program outcomes in baseline characteristics.Population: Differences between the population numbers in the rows and the overall numbers are due to participant non-response.
The investigators will assess changes in student self-reported feelings about shellfish harvesting relevant to the Theory of Planned Behavior, including whether students think shellfish harvesting is enjoyable and rewarding, whether peers approve of shellfish harvesting and participate in shellfish harvesting, and whether students feel empowered to make shellfish harvesting decisions, with pre-unit and post-unit written evaluations that collect information on students' feelings about shellfish harvesting, measured using Likert scale questions. Likert-scale responses ranged from disagree (1) to agree (5). Here we report post education unit outcomes. We report pre education unit outcomes in baseline characteristics. Questions 1, 2, 3, 4, 5, 9, 10, 11, 12, 13, and 14 reflect this outcome measure. Questions 10 and 13 are used to assess both this outcome and primary outcome 1 and so are reported under both measures.
Outcome measures
| Measure |
Middle School Education Program
n=50 Participants
The education intervention centers around teaching children about local traditional ecological knowledge and traditional harvesting and gathering practices, including those for shellfish.
The education program is divided into three units, following other tribal education programs. Primary data collection will be conducted by unit to assess student learning for each unit. The first unit will cover an introduction to shellfish, harmful algal blooms (HAB), and paralytic shellfish poisoning (PSP). The second unit will cover herring and how herring relates to Tlingit culture. The third unit will focus on intertidal zones as zones relate to Tlingit culture.
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|---|---|
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Student Assessment Questionnaire of Feelings About Shellfish Harvesting Relevant to the Theory of Planned Behavior.
1: Subsistence clam harvesting is enjoyable
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4.2 Scores on a scale
Standard Deviation 0.8
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Student Assessment Questionnaire of Feelings About Shellfish Harvesting Relevant to the Theory of Planned Behavior.
2: Subsistence clam harvesting is rewarding
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4.2 Scores on a scale
Standard Deviation 1.0
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Student Assessment Questionnaire of Feelings About Shellfish Harvesting Relevant to the Theory of Planned Behavior.
3: People I care about approve of clam harvest
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4.4 Scores on a scale
Standard Deviation 0.7
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Student Assessment Questionnaire of Feelings About Shellfish Harvesting Relevant to the Theory of Planned Behavior.
4: Peers participate in clam harvesting
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3.1 Scores on a scale
Standard Deviation 1.2
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Student Assessment Questionnaire of Feelings About Shellfish Harvesting Relevant to the Theory of Planned Behavior.
5: Whether I harvest is up to me
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4.4 Scores on a scale
Standard Deviation 0.7
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Student Assessment Questionnaire of Feelings About Shellfish Harvesting Relevant to the Theory of Planned Behavior.
9: Checking website before clamming is rewarding
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4.3 Scores on a scale
Standard Deviation 0.8
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Student Assessment Questionnaire of Feelings About Shellfish Harvesting Relevant to the Theory of Planned Behavior.
10: Checking website before clamming is easy
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4.2 Scores on a scale
Standard Deviation 0.9
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Student Assessment Questionnaire of Feelings About Shellfish Harvesting Relevant to the Theory of Planned Behavior.
11: Those I get clams with approve of check site
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4.3 Scores on a scale
Standard Deviation 0.9
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Student Assessment Questionnaire of Feelings About Shellfish Harvesting Relevant to the Theory of Planned Behavior.
12: People like me will check website before clam
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3.5 Scores on a scale
Standard Deviation 1.3
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Student Assessment Questionnaire of Feelings About Shellfish Harvesting Relevant to the Theory of Planned Behavior.
13: I am confident I can check website before clam
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3.9 Scores on a scale
Standard Deviation 1.3
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Student Assessment Questionnaire of Feelings About Shellfish Harvesting Relevant to the Theory of Planned Behavior.
14: Checking website is up to me
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4.4 Scores on a scale
Standard Deviation 1.0
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SECONDARY outcome
Timeframe: Post education (following the semester-long program) at 10 weeks.Population: Differences between the participant numbers in the rows and the overall numbers are due to 30 total post-program interviews being conducted. Of the 50 participants in the study, 1 did not consent to participate in interviews. Of the 49 consented participants, interviews were conducted with 37 participants at the start of the program and 30 participants at the end of the program. Fewer interviews were conducted than the number of those consented because of scheduling and attendance constraints.
The investigators conducted interviews at the beginning and end of each semester's program (before and after all units). To analyze data, a codebook was generated using both inductive and deductive approaches. First, codes were identified based on major themes in the interview protocol and relevant to the TPB. Next, all transcripts were reviewed to identify further themes not captured in deductively developed codes. This grounded theory approach was important to identify new themes raised by participants. Data was coded and analyzed using Dedoose software. Here we report themes raised in post-program interviews. Participant quotations reflecting these themes can be found in the published paper from this study.
Outcome measures
| Measure |
Middle School Education Program
n=30 Participants
The education intervention centers around teaching children about local traditional ecological knowledge and traditional harvesting and gathering practices, including those for shellfish.
The education program is divided into three units, following other tribal education programs. Primary data collection will be conducted by unit to assess student learning for each unit. The first unit will cover an introduction to shellfish, harmful algal blooms (HAB), and paralytic shellfish poisoning (PSP). The second unit will cover herring and how herring relates to Tlingit culture. The third unit will focus on intertidal zones as zones relate to Tlingit culture.
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|---|---|
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Student Interviews to Qualitatively Assess Student Learning From All Educational Units and Changes in Student Perspectives, Behaviors, and Behavioral Intentions Related to Shellfish Harvesting.
Some/ high knowledge of risk reduction strategies
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20 Participants
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Student Interviews to Qualitatively Assess Student Learning From All Educational Units and Changes in Student Perspectives, Behaviors, and Behavioral Intentions Related to Shellfish Harvesting.
Some/ high knowledge of SEATOR resources
|
28 Participants
|
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Student Interviews to Qualitatively Assess Student Learning From All Educational Units and Changes in Student Perspectives, Behaviors, and Behavioral Intentions Related to Shellfish Harvesting.
Some/ high knowledge of PSP
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26 Participants
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SECONDARY outcome
Timeframe: Data collection one year following participation in the educational program.Population: When we closed the study, only 7 participants had completed the program at least one year prior and were available for one year post-program recontact. Of these 7 participants, 4 completed the follow-up survey.
The investigators will follow up with participants one year after participation in the educational program to assess whether participants have had any behavior changes related to subsistence shellfish consumption, measured using Likert scale questions. Likert-scale responses ranged from disagree (1) to agree (5).
Outcome measures
| Measure |
Middle School Education Program
n=4 Participants
The education intervention centers around teaching children about local traditional ecological knowledge and traditional harvesting and gathering practices, including those for shellfish.
The education program is divided into three units, following other tribal education programs. Primary data collection will be conducted by unit to assess student learning for each unit. The first unit will cover an introduction to shellfish, harmful algal blooms (HAB), and paralytic shellfish poisoning (PSP). The second unit will cover herring and how herring relates to Tlingit culture. The third unit will focus on intertidal zones as zones relate to Tlingit culture.
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|---|---|
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Follow-up Student Assessment Questionnaire of Student Learning to Assess Lasting Behavioral Changes From Intervention Participation.
7: I have participated in clam harvesting
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5 Scores on a scale
Standard Deviation 0
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Follow-up Student Assessment Questionnaire of Student Learning to Assess Lasting Behavioral Changes From Intervention Participation.
8: Learning clam safety I am more willing to clam
|
4.75 Scores on a scale
Standard Deviation 0.5
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Follow-up Student Assessment Questionnaire of Student Learning to Assess Lasting Behavioral Changes From Intervention Participation.
15: I intend to check website to decide to clam
|
5 Scores on a scale
Standard Deviation 0
|
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Follow-up Student Assessment Questionnaire of Student Learning to Assess Lasting Behavioral Changes From Intervention Participation.
16: I have used website to inform decision to clam
|
3.5 Scores on a scale
Standard Deviation 1.9
|
Adverse Events
Middle School Education Program
Serious adverse events
Adverse event data not reported
Other adverse events
Adverse event data not reported
Additional Information
Matthew O. Gribble
Department of Medicine, Division of Occupational, Environmental, and Climate Medicine, University of California
Results disclosure agreements
- Principal investigator is a sponsor employee
- Publication restrictions are in place