Awards and Performance Evaluation PersMgmt Part 1 Awds/Eval MAR 2004.
Representative Sampling Presented at the AWDS Task Force’s Marketing Workshop Big Sky, Montana...
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![Page 1: Representative Sampling Presented at the AWDS Task Force’s Marketing Workshop Big Sky, Montana Friday, September 20, 2002 Len Singel, AWDS Coordinator.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e225503460f94b0f084/html5/thumbnails/1.jpg)
Representative Sampling
Presented at the AWDS Task Force’s Marketing Workshop
Big Sky, Montana Friday, September 20, 2002
Len Singel, AWDS Coordinator
![Page 2: Representative Sampling Presented at the AWDS Task Force’s Marketing Workshop Big Sky, Montana Friday, September 20, 2002 Len Singel, AWDS Coordinator.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e225503460f94b0f084/html5/thumbnails/2.jpg)
Overview
Definitions
Reducing Error
Sample Creation
Examples
![Page 3: Representative Sampling Presented at the AWDS Task Force’s Marketing Workshop Big Sky, Montana Friday, September 20, 2002 Len Singel, AWDS Coordinator.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e225503460f94b0f084/html5/thumbnails/3.jpg)
Definitions
Population – consists of all the units (individuals, households, organizations) to which you desire to generalize survey results
Sample Frame – list from which your sample is drawn
![Page 4: Representative Sampling Presented at the AWDS Task Force’s Marketing Workshop Big Sky, Montana Friday, September 20, 2002 Len Singel, AWDS Coordinator.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e225503460f94b0f084/html5/thumbnails/4.jpg)
Definitions
Sample – the set of respondents selected from a larger population for the purpose of a survey
Completed Sample – consists of all units that return completed questionnaires (instruments)
![Page 5: Representative Sampling Presented at the AWDS Task Force’s Marketing Workshop Big Sky, Montana Friday, September 20, 2002 Len Singel, AWDS Coordinator.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e225503460f94b0f084/html5/thumbnails/5.jpg)
Definitions
Coverage Error – results from every unit in the Survey Population not having a known, non-zero chance of being included in the sample
Sampling Error – the result of collecting data from a subset, rather than all of the members of the sampling frame
![Page 6: Representative Sampling Presented at the AWDS Task Force’s Marketing Workshop Big Sky, Montana Friday, September 20, 2002 Len Singel, AWDS Coordinator.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e225503460f94b0f084/html5/thumbnails/6.jpg)
Avoiding Coverage Error
![Page 7: Representative Sampling Presented at the AWDS Task Force’s Marketing Workshop Big Sky, Montana Friday, September 20, 2002 Len Singel, AWDS Coordinator.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e225503460f94b0f084/html5/thumbnails/7.jpg)
How to Reduce Coverage Error?
Make certain your list contains everyone in the Survey Population Unique, non-repeating Sampling Units
Update & Properly maintain your list
Have your list contain other information that can be used to improve your survey
![Page 8: Representative Sampling Presented at the AWDS Task Force’s Marketing Workshop Big Sky, Montana Friday, September 20, 2002 Len Singel, AWDS Coordinator.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e225503460f94b0f084/html5/thumbnails/8.jpg)
How Large Should Your Sample be?
Sample does not have to be arbitrarily selected
ALL THAT IS REQUIRED:Knowing about your study population
AND
Knowing your survey objectives
![Page 9: Representative Sampling Presented at the AWDS Task Force’s Marketing Workshop Big Sky, Montana Friday, September 20, 2002 Len Singel, AWDS Coordinator.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e225503460f94b0f084/html5/thumbnails/9.jpg)
How Large Should Your Sample Be?
Sample Size Depends On:
How much sampling error can be tolerated
Population size
Variation of Population (50/50 or 80/20)
Amount of Confidence
![Page 10: Representative Sampling Presented at the AWDS Task Force’s Marketing Workshop Big Sky, Montana Friday, September 20, 2002 Len Singel, AWDS Coordinator.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e225503460f94b0f084/html5/thumbnails/10.jpg)
Does Size Matter
![Page 11: Representative Sampling Presented at the AWDS Task Force’s Marketing Workshop Big Sky, Montana Friday, September 20, 2002 Len Singel, AWDS Coordinator.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e225503460f94b0f084/html5/thumbnails/11.jpg)
Small Populations
Population Size
Sample Size for 95 Percent Confidence
+ 3 %
Sampling Error
+ 5 %
Sampling Error
50/50 Split
80/20 Split
50/50 Split
80/20 Split
100 92 87 80 71
500 341 289 217 165
1,000 516 406 278 198
5,000 880 601 357 234
![Page 12: Representative Sampling Presented at the AWDS Task Force’s Marketing Workshop Big Sky, Montana Friday, September 20, 2002 Len Singel, AWDS Coordinator.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e225503460f94b0f084/html5/thumbnails/12.jpg)
Larger Populations
Population Size
Sample Size for 95 Percent Confidence
+ 3 %
Sampling Error
+ 5 %
Sampling Error
50/50 Split
80/20 Split
50/50 Split
80/20 Split
10,000 964 639 370 240
50,000 1,045 674 381 245
100,000 1,056 678 383 245
1,000,000 1,066 682 384 246
![Page 13: Representative Sampling Presented at the AWDS Task Force’s Marketing Workshop Big Sky, Montana Friday, September 20, 2002 Len Singel, AWDS Coordinator.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e225503460f94b0f084/html5/thumbnails/13.jpg)
3 Easy Steps to Sampling
1) Identify your Target Population
2) Put together a Population List
3) Select the Sample
![Page 14: Representative Sampling Presented at the AWDS Task Force’s Marketing Workshop Big Sky, Montana Friday, September 20, 2002 Len Singel, AWDS Coordinator.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e225503460f94b0f084/html5/thumbnails/14.jpg)
Hey, Wait a Minute…..
I DON’T KNOW HOW TO
SELECT THE SAMPLE!!!
![Page 15: Representative Sampling Presented at the AWDS Task Force’s Marketing Workshop Big Sky, Montana Friday, September 20, 2002 Len Singel, AWDS Coordinator.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e225503460f94b0f084/html5/thumbnails/15.jpg)
Sampling Methods
Probability Simple Random Sampling (SRS) Systematic Sampling
Nonprobability (Purposeful)
![Page 16: Representative Sampling Presented at the AWDS Task Force’s Marketing Workshop Big Sky, Montana Friday, September 20, 2002 Len Singel, AWDS Coordinator.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e225503460f94b0f084/html5/thumbnails/16.jpg)
Probability Sampling Method
Simple Random Sampling (SRS) Each member of the target population has an equal chance of
being selected All elements are selected randomly – CAN BE
CUMBERSOME!!!
Systematic Sampling Members of the target population have an equal chance of being
selected Only the first element is selected randomly; rest selected
systematically (every 5th, 10th, …)
![Page 17: Representative Sampling Presented at the AWDS Task Force’s Marketing Workshop Big Sky, Montana Friday, September 20, 2002 Len Singel, AWDS Coordinator.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e225503460f94b0f084/html5/thumbnails/17.jpg)
Purposeful Sampling Method
Depends on subjective judgment Selected because it is convenient or typical
All members do not have the same chance of being selected
![Page 18: Representative Sampling Presented at the AWDS Task Force’s Marketing Workshop Big Sky, Montana Friday, September 20, 2002 Len Singel, AWDS Coordinator.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e225503460f94b0f084/html5/thumbnails/18.jpg)
Purposeful Sampling Method
Appropriate for: Exploratory Research Focus Groups Organizing Committees Building Networks
Do not use if your goal is to learn about the larger population
–Results are not generalizable!!
![Page 19: Representative Sampling Presented at the AWDS Task Force’s Marketing Workshop Big Sky, Montana Friday, September 20, 2002 Len Singel, AWDS Coordinator.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e225503460f94b0f084/html5/thumbnails/19.jpg)
Example 1: Successful Hunting Experience
Target Population: 1 million Deer Hunters
Survey Objectives: Learn about Hunting Success
Acceptable Sampling Error: + 3%
Confidence Level: 95%
Population Variation: 80/20
![Page 20: Representative Sampling Presented at the AWDS Task Force’s Marketing Workshop Big Sky, Montana Friday, September 20, 2002 Len Singel, AWDS Coordinator.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e225503460f94b0f084/html5/thumbnails/20.jpg)
Example 1:Successful Hunting Experience
Population List: Automated Licensing Database
Sample Size: 683
Sampling Method: Systematic Sampling
![Page 21: Representative Sampling Presented at the AWDS Task Force’s Marketing Workshop Big Sky, Montana Friday, September 20, 2002 Len Singel, AWDS Coordinator.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e225503460f94b0f084/html5/thumbnails/21.jpg)
Example 2:Female Hunter Perceptions
You know you want to study female waterfowl hunters and their satisfaction levels.
But… You do not know much about them
AND You do not know your survey objectives
![Page 22: Representative Sampling Presented at the AWDS Task Force’s Marketing Workshop Big Sky, Montana Friday, September 20, 2002 Len Singel, AWDS Coordinator.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e225503460f94b0f084/html5/thumbnails/22.jpg)
Example 2:Female Hunter Perceptions
Target Population: Female Waterfowl Hunters (n = 100?)
Survey Objectives: Explore their satisfaction levels
Acceptable Sampling Error: + 3%
Confidence Level: 95%
Population Variation: 50/50 or 80/20 ???
![Page 23: Representative Sampling Presented at the AWDS Task Force’s Marketing Workshop Big Sky, Montana Friday, September 20, 2002 Len Singel, AWDS Coordinator.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e225503460f94b0f084/html5/thumbnails/23.jpg)
Example 2:Female Hunter Perceptions
Source: Automated Licensing Database
Sample Method: ??
Sample Size:??
![Page 24: Representative Sampling Presented at the AWDS Task Force’s Marketing Workshop Big Sky, Montana Friday, September 20, 2002 Len Singel, AWDS Coordinator.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e225503460f94b0f084/html5/thumbnails/24.jpg)
Example 2:Female Hunter Perceptions
The Solution! Conduct Exploratory Research
Increase Sampling Error to + 10%
Hold a series of focus groups (n = 50)
![Page 25: Representative Sampling Presented at the AWDS Task Force’s Marketing Workshop Big Sky, Montana Friday, September 20, 2002 Len Singel, AWDS Coordinator.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e225503460f94b0f084/html5/thumbnails/25.jpg)
Example 2:Female Hunter Perceptions
Enables you to… Learn about Population Variation Learn about General Characteristics Define Survey Objectives Select appropriate sample size to be surveyed.
![Page 26: Representative Sampling Presented at the AWDS Task Force’s Marketing Workshop Big Sky, Montana Friday, September 20, 2002 Len Singel, AWDS Coordinator.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e225503460f94b0f084/html5/thumbnails/26.jpg)
Review
What does sample size depend on?
What are the 3 steps to sampling?
Does size matter?
![Page 27: Representative Sampling Presented at the AWDS Task Force’s Marketing Workshop Big Sky, Montana Friday, September 20, 2002 Len Singel, AWDS Coordinator.](https://reader036.fdocuments.net/reader036/viewer/2022081519/56649e225503460f94b0f084/html5/thumbnails/27.jpg)
Sources
Dillman, D.A. 2000. Mail and Internet Surveys: The Tailored Design Method. John Wiley & Sons, Inc. 464pp.
Salant, P. and D.A. Dillman. 1994. How to Conduct your Own Survey. John Wiley & Sons, Inc. 232pp.