Questions re Internet Use

• How many/what percent use it• How often, how much• For what purposes• From where (home, office, public-

access computer)• Differences

– by geography, demographics, other characteristics of interest

– Differences that require public policy intervention?

Reasons for Interest

• policy implications– Educational, economic effects of “digital

divide”• National• International

– Government mitigation?

• business implications

Assumptions

• Internet access is good– Educational effects– Employment effects– Other economic effects– Participation in society

• There are policy reasons for society as a whole, government to be concerned

• International issues:– Economic opportunity– Participation in global community– Democratizing effects

Our interest

• Survey-based social science research– Methods– Uses– Interpretation

• Key findings

A Nation Online , Feb., 2001

• 5th in a series measuring US digital divide• Less emphasis on haves and have-nots • parts to the study:

– Computer use and internet use– Online activities– How and where people go online– Digital generation: young people– Digital workplace– People with disabilities– The unconnected– Reductions in inequality

Survey research

• Determine goals• Design survey

– Questionnaire– Sample, sampling method– Administration– Analysis

• Pretest• Redesign• Administer• Code• Edit• Analyze data• Interpret findings

Goals: Uses of survey research

• Demographics– Age, race, income, urban/rural, education…

• Behavior (self-reports)• Opinions, perceptions

Some Limits of Surveys

• Reaching users is easier than non-users• Relies on voluntary cooperation, possibly

biasing the sample• Questions have to be unambiguous,

amenable to short answers• You only get answers to the questions you

ask; you generally don’t get explanations• The longer or more complex the survey the

less cooperation

Some alternatives

• Diary studies• Critical incident techniques• Monitoring, behavior tracking• Experiments

– HomeNet study gave people computers and tracked them over time

– Validity problems?

Sampling

Sample design

• Probability samples– random– stratified random– cluster– Systematic– GOAL: Representative sample

• Non-probability sampling– convenience sampling– purposive sampling– quota sampling

Time

• Cross-sectional studies– Collect data now from experienced and new users– Assumes that the two groups differ mainly in

experience, and conditions similar x time

• Cohort studies– Follow same population tho samples may differ; e.g.

people who first used Internet in 1995; college grads from 1990

• Panel studies– Follow same group over time– Track changes– However:

• People drop out

Administering Surveys

• Other-administered– Phone– In person

• Self-administered– Mail– Web– Paper in convenient place…

Active vs passive sampling

• active: solicit respondents– Send out email– Phone– Otherwise reach out to them– Follow up on non-respondents if possible

• passive – e.g. on web site– Response rate may be unmeasurable– heavy users may be over-represented– Disgruntled and/or happy users over-

represented

Response Rates

• low rates may > bias– Whom did you miss? Why?

• How much is enough? – Babbie: 50% is adequate; 70% is very good

• May help if they understand purpose– Don’t underestimate altruism

• Incentives may increase response– Reporting back to respondents as a way of getting

response

A Nation Online Sample, p. 92

• [Universe – US residents]• population

– US residents age 3+ during week of September 16-22, 2001

• sample– CPS survey sample from 1990 decennial census, updated for

new construction– sampling unit: households – size: 57,000 households

• units of analysis– Households 57,000– Individuals age 3+: 137,259

• Survey administration: have to go to CPS to find out: phone or in person

• Respondent: a person >= 15 years old knowledgeable about everyone in household

Variables

• Dependent, Independent• Conceptualization• Operationalization

Definitions/Operationalization

• A Nation Online:– Individuals age 3+– “Is there a computer or

laptop in this household?”– “Does anyone in this

household connect to the Internet from home?”

– “Other than a computer or laptop, does anyone in this household have some other device with which they can access the Internet, such as:

–  cellular phone or pager–  a personal digital

assistant or handheld device

– a TV-based Internet device– something else/ specify”

Sept. 2001: 143,000,000

• Nielsen//NetRatings – “Internet usage estimates

are based on a sample of households that have access to the Internet and use the following platforms: Windows 95/98/NT, and MacOS 8 or higher”

– “The Nielsen//NetRatings Internet universe is defined as all members (2 years of age or older) of U.S. households which currently have access to the Internet.”

– Sept. 2001: 168,600,000• (+18%)

Questionnaire construction:

• Questions• Ordering• Wording

Error

• “All statistics are subject to sampling error, as well as non-sampling error such as survey design flaws, respondent classification and reporting errors, data processing mistakes and undercoverage. The Census Bureau has taken steps to minimize errors in the form of quality control and edit procedures to reduce errors made by respondents, coders, and interviewers.” p. 92

• The Census Bureau determined that some of the data were statistically insignificantfor meaningful analysis because the sample from which they were derived was too small.

Sampling error

• A sample statistic is an estimate of a population parameter

• Table 1-1: Internet use by % of state population – 90% confidence interval (the chances are 90% that the true value falls in this range)– U.S.: 53.6 – 54.1 – California: 50.0 – 53.3– South Carolina: 44.6 – 50.7

• Size of confidence interval a function of– Sample size (NOT population size)– Distribution of sample results

• Overlapping confidence intervals = not statistically significant difference– Davis 52% +- 3%– Simon 48% +- 3%