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Web-Based Research:Issues, Problems and an
Example Technique
John H. Krantz
Hanover College
Outline
Brief History Issues in Internet Research An Example Method Problems and Solutions
History
Email for 2-3 Decades 1995
Krantz, Ballard, & Scher (1997) Within Subjects Reips (1997) Between Subjects First True Web Experiments
July 1995 List of Online Psychological Research – sponsored by APS for awhile http://psych.hanover.edu/research/exponnet.html Almost 200 studies and study sites listed
Why Do Internet Research
Musch & Reips (2000) Sample Size Statistical Power High Speed Ability to reach participants in other countries High external or ecological validity Low cost Ability to replicate a lab experiment with more
power Special populations
Issues
Is the Sample Representative Yes and No
Important to remember base of comparison Ideal vs. Lab
Krantz & Dalal (2000) Much more diverse that most lab samples Especially in age and education range Race is generally limited as is nationality
Sample Characteristics: Gender
Are Internet Samples Male Dominated? Krantz & Dalal (2000) % Female
GVU 1st (1994) 5% Reips (1996) English: 43%
German: 18% Krantz, et al. (1997) 44% Pasveer & Ellard (1998) 3rd Study 71%
More Recent Caddell & Utt (2004) 77% Meyerson & Tryon (2003) 45%
Sample Characteristics: Age
Are we still testing college sophomores? Krantz, et al. (1997) 43% > 30 Smith & Leigh (1997) 35% > 30 Pasveer & Ellard (1998) 45% > 25 GVU 1st 36% > 30 Caddell & Utt (2004) 60% > 30 Pattison & Rouse(2003) 16% > 30
Is the College Sophomore be Making a Comeback
Plot of activity of Psychological Research on the Net
Pattison & Rouse (2004) 76% 18-22
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Sample Characteristics: Race
How diverse are the samples? Unfortunately in general samples, diversity is still
limited Krantz et al. (1997) 89% White Smith & Leigh (1997) 86% White GVU 10th (1998b) 87% White O’Neil, Penrod, & Bornstein (2003) 82% White Meyerson & Tryon (2003) 93% White
However, as will be discussed later, web can make it possible to access special populations
Sample Characteristics: Nationality
Where to do the subjects come from? Largely North American, even US, even in
some European studies Krantz, et al. (1997) 86% N. Am. Senior, et al (1999) >80% N. Am
This study was conducted in England.
Is the Data Any Good
Emphatically Yes
Data Quality: Direct Comparisons
A number of studies, still, run both laboratory and internet samples.
Krantz, et al. (1997) Regression of web means on laboratory
samples (even though different types of samples):
lab mean = 1*(Web mean) + 0
r2 = .99
Compare to Established Data
Compare web results to previously published data sets
Myerson & Tryon (2003) Studied Sexual Boredom Scale of Watt &
Ewing (1996) Matched sample characteristics Found same internal consistency Form of administration was not a significant
factor
Direct Validity Comparison
Use same techniques to validate results Pasveer & Ellard (1998) Developed new scale Internal consistency Psychomectric properties
Data Validity: Arguments
Reips (2000) Statistical Power Limited Sample Population Limited External Validity Less than Optimal Voluntariness Motivational Confounding Experimenter Bias Nontransparency Limitations of what is feasible to research
Interesting Deviations
Stern & Faber (1997) Milgram’s lost letter technique Milgram, sent on Stern & Faber, returned to sender From doing favor to doing easy task
Often effects are smaller
Getting Subjects: General
http://psych.hanover.edu/research/exponnet.html
Other Pages: Social Psychology:
http://www.socialpsychology.org/expts.htm The Web Experiment List:
http://genpsylab-wexlist.unizh.ch/
Getting Subjects: Special Populations
Advertising Email Groups
Careful, get permission Can be thought spam Netiquette
Discussion Groups Same, permission
Sample Method for Doing Survey
Birnbaum, M. H. (2001). Introduction to Behavioral Research on the Internet. Upper Saddle River, NJ: Prentice Hall.
Lots of resources at http://ati.fullerton.edu/ NSF sponsored classes at Fullerton on Social
Psychology One more next January, look for the
announcement at this site
First Step: Where to put it
Setting up a server can be easy Apache web server http://www.apache.org Most popular server Freeware Any computer connected to web is now a
server May have issues of firewalls & dynamic IP
addresses
Second Step: SurveyWiz
In Birnbaum (2001) Also linked to from http://ati.fullerton.edu/
Under Birnbaum’s page Freely available We will build a very short survey to illustrate
Forms
SurveyWiz uses web forms to collect data What are forms:
Elements to allow web page viewers to input This data is then sent back to the server to be
processed
SurveyWiz What the page looks like My Take Can edit it with any web page editor
Examples I have done this year
Caddell & Utt Pattison & Reese
Third Step: Collecting the data
First way, let Birnbaum do it for you SurveyWiz is set up this way <FORM
action=http://psych.fullerton.edu/cgi-win/polyform.exe/generic method=post>
FTP://guest:[email protected] You can type in the address box of your browser.
Note that this is FTP site. At the present time, password is guest99, as shown above, and permits download only.
Keeping the Data Local
Second, get this perl script (found at http://psych.fullerton.edu/mbirnbaum/programs/PERL_script2.htm)
The script and instructions are at this site Written by Billy Schmidt
Also change code in form command At my school the line reads: <FORM
action=http://psych.hanover.edu/cgi-bin/survey_wiz.pl method=post>
What is CGI
Common Gateway Interface Method for other programs to interact with
web servers In this case, this perl program takes data
from web forms and stores them in a file Stores data in Excel or SPSS readable files
Fourth Step: Example Data File
Data File Data coding scheme: all variable names
begin two numbers, see example The perl program sorts the variables by
numerical order
Another Method of Survey Generation
Schmit’s Survey Assistant He manages data More flexibility http://or.psychology.dal.ca/~wcs/hidden/
home.html
What Do I Need?
At NSF ATI site List of software resources
What Problems are important
Musch & Reips (2000) – 5 point scale No control over participant’s behavior 3.6 No control over motivation
3.4 Inability of participants to ask questions 3.3 Nonrepresentative sample
2.9 Manipulation and fraud 2.4 Ethical problems 1.5
Problems
Eliminating Multiple Entries Dropout Security Data Integrity
Multiple Entries
People submit too fast, while waiting for feedback
People will fake being two people Usually have same IP address SurveyWiz and most other methods, sends
the IP address of machine where survey is being taken
Can eliminate more than one from same IP, e.g. Schmidt (1997)
Security & Data Integrity
If on public server, others can access data and download
Others might fake pages to send data (unlikely)
Keep data in non-public directories so only researchers have access
Have CGI check for origin of survey to make sure it is yours (Schmidt, 1997)
Dropout
People will come but not finish Or data is incomplete Survey will sends a complete signal to help
you track Can use: (O’Neil, Penrod, & Bornstein, 2003)
Short sweet Financial incentives. If multiple pages to survey, several pages warm-
up so not drop-out during
Ethical Issues
Should not think of Ethical Issues of Web Research Alone
Compare to Ethics of doing Traditional Research
Not let our comfort with what we have done blind us to those problems
Conclusion
Many Benefits Easy Methods Easy Resources Not alternative to traditional methods A new tool still needs to be used thoughtfully