What are Quantitative Data?

Pieces of information that can be counted mathematically

Strengths	Limitations
Findings can be generalized, if selection process well-designed and sample is representative of study population	Related secondary data sometimes not available, or accessing available data is difficult/impossible
Relatively easy to analyze	Difficult to understand context of program activities
Data can be very consistent, precise, reliable	Data may not be robust enough to explain complex issues
Data collection is usually cost efficient

How do you collect Quantitative Data? Surveys

• Most common method
• Self-administered or by someone else
• Face-to-face, telephone, mail, web-based

Secondary Data

• Often used in conjunction with survey data
• Includes census data, knowledge/attitude/behavior (KABB) studies, criminal justice statistics, performance data, non-confidential client information, agency progress reports, etc.

Qualitative Data and Evaluation Methods

What are Qualitative Data?

Strengths	Limitations
Complement and refine quantitative data	Findings usually can not be generalized to the study population or community
Provide more detailed information to explain complex issues	More difficult to analyze; don’t fit neatly in standard categories
Multiple methods for gathering data on sensitive subjects	Data collection is usually time consuming and costly

How do you collect Qualitative Data? 

Observations

• Looking at what is happening rather than directly questioning participants
• Used to better understand behaviors, their social context and meanings attached to them
• Useful for certain populations - children, infants
• Can identify unanticipated outcomes

Interviews (in-depth, individual)

• Usually provide rich data, details, insights from program participants and stakeholders about their experiences, behaviors and opinions
• Particularly useful for complex or sensitive subjects
• Use open-ended questions

Focus Groups

• 8-12 people selected by non-random method, share some characteristics or experience relevant to the evaluation, ideally do not know each other, respond to questions from group facilitator
• Use group dynamics to generate data and insights
• Useful for generating ideas and strategies, defining problems in project implementation, assist with interpreting quantitative findings
• Open-ended questions or topics designed to stimulate discussion; topics usually broader than interview questions

Usually gathered by surveys from large numbers of respondents selected randomly

Secondary data such as census data, government statistics, etc. often included in quantitative evaluations

Analyzed using statistical methods

Best used to answer what, when and who questions

Not well suited to how and why questions

Usually gathered by observations, interviews or focus groups

May also be gathered from written documents and through case studies

Less emphasis on counting numbers of people who think or behave in certain ways and moreemphasis on explaining why people think and behave in certain ways

Involves smaller numbers of respondents

Utilizes open-ended questionnaires or protocols

Best used to answer how and why questions

Not well suited to what, when and who questions