Presentation on theme: "Research Design (1) develop concepts derived from ideas, theories, or prior research (2) Translate concepts into measurable variables (operationalize)"— Presentation transcript:
Research Design (1) develop concepts derived from ideas, theories, or prior research (2) Translate concepts into measurable variables (operationalize) (3) select the most appropriate research method to gather data (surveys, experiments, field methods, etc.) based on the goals of the project (to describe, explain, predict, etc.) (4) choose a sampling strategy (5) plan how to collect the data and who will do it (6) decide on the relevant statistical and analytical tools (7) describe plans for interpreting and analyzing the results and writing a final report
Concepts & Variables Concept: an idea, a general mental formulation summarizing specific occurrences, such as “Gender” Construct: abstract concepts, such as “anomie” Variables: concepts made measurable and that vary across a sample (not a constant) Values: the attributes or categories of a variable Operationalization: the process specifying how a variable is to be measured
Concepts & Variables Example 1: Child Rearing Values in Urban China Hong Xiao, Sociological Perspectives 43:3, 2002, Child socialization theory suggests a link between social class and child-rearing values. Middle class parents value children’s autonomy, whereas working class parents endorse conformity. However, the effect of class and education differ in non-market and capitalist economies. Concepts: social class, autonomy, education (autonomy defined by dictionary as “the condition or quality of being self-governing”) Variables: autonomy of the job: how much decision-making in the job (“how much” implies a variable amount, not all the same amount) Operationalize: ask self-report using values of 1 (category: least job freedom) to 10 (most job freedom)
Concepts & Variables Example 2: Mexican-Origin Women's Employment Instability Roberto De Anda, Sociological Perspectives 43:3, 2002, Compares the causes & earning consequences of employment instability among Mexican-origin women. Workers who had one or more spells of unemployment during the year or involuntarily worked part-time during the entire year are said to have experienced employment instability. Results show that Mexican-origin women with low levels of schooling, and are immigrants are highly vulnerable to employment instability.
Concepts & Variables P. 425: “The operationalization of labor market experience variables strictly adheres to the official definition of labor force concepts used by the Bureau of Labor Statistics. Thus the unstable active category includes workers who experienced at least one episode of unemployment during the year or yearlong, involuntary part-time work…. A person is considered unemployed if he or she is without a job and is actively looking for work.” Persons are considered part-time workers if they work less than thirty-five hours per week. Part-year workers are defined as persons who work less than fifty weeks during the year. “Respondents are asked directly if they want and are available for full-time work.” Concept: labor force Variables: labor force experience: unstable active: part-time, year-long Operationalize : ask directly – want work & are available
Hypothesis Untested statements that specify a relationship between two or more variables are called hypotheses. A hypothesis is a hunch derived from an informed reading of the literature, theory, or personal observations and experience, and must be capable of being tested. The outcome we are seeking to understand is called the dependent variable and we hypothesize that its variability in our sample depends on particular explanations or causes. The explanations or causes (or predictors, if you are trying to predict the variation in the dependent variable) are called the independent variables.
Type of Hypotheses Null two-directional (two-tailed): There is no relationship between the number of peers teenagers have who engage in delinquent acts and the amount of delinquency they engage in. Positive two-directional: There is a relationship between the number of peers teenagers have who engage in delinquent acts and the amount of delinquency they engage in. Positive one-directional: Teenagers who have more peers who engage in delinquent acts are more likely to engage in delinquency themselves. More peersmore delinquency Inverse (negative) one-directional: Teenagers who have high levels of support from parents are less likely to engage in delinquent acts. (more parental support less delinquency) Research question: Is there a relationship between peers and delinquency? Note: none of these is about one person; hypotheses are about aggregated groups of people.
Hypothesis Exercise: Write hypotheses about a relationships between respondents’ ages and hours viewing TV per week. Which is the independent and which is the dependent variables? Two-directional null hypothesis: There is no relationship between respondents’ ages and the number of hours viewing TV per week. Alternative (positive): There is a relationship between age and hours of TV viewing. One-directional positive hypothesis: Older respondents watch more TV, or younger respondents watch less TV. One-directional inverse (negative) hypothesis: Older respondents watch less TV, or younger respondents watch more TV.
Hypotheses De Anda: “Mexican-Origin Women’s Employment” “Workers employed in core sectors of the economy will have less employment instability.” “Workers employed in periphery service sectors of the economy will receive less than average wages.” Dependent variables? Amount of employment stability Amount of wages (salary) Independent variable? Type of employment sector One-tailed or two? One directional
Levels of Measurement A discrete variable has values that do not contain additional information between those values. Number of books in a library Rankings of the Top 10 selling CDs A continuous variable, on the other hand, has values that have information between those values. Weight Height
Levels of Measurement A nominal variable: a discrete measure whose values represent named categories of classification. For coding purposes, they can be assigned arbitrary numerals. The variable “favorite color” is measured nominally City you were born in [1=NYC, 2=LA, 3=Seattle, etc.] An ordinal variable is a discrete measure with the category values in sequence from high to low, or low to high. For coding purposes, they can be assigned arbitrary numerals. Ranking (rank order) 3=bad, 2=OK, 1=great Social class (lower, middle, upper) Strongly Agree (1) to Strongly Disagree (4)
Levels of Measurement An interval variable is a measure whose numbers are in order with equal size intervals, but have no absolute or fixed zero as a starting point. Temperature (Zero and below zero are actual measures) A ratio variable is a measure whose numbers are in order with equal size intervals and with an absolute zero. Height (no such thing as negative height) Salary in dollars ($20/hr. is twice as much as $10/hr) These will be referred to as Interval/Ratio measures.
Levels of Measurement The levels of measurement are themselves ordinal: Nominalsimplest, non-mathematical measure Ordinal Interval Ratiomost complex, mathematical measure V Variables with two values or categories are often called dichotomous or dummy variables: These may be treated as any level of measurement. 1 = Tall0 = Did not graduate 2 = Short1 = Graduated O Ordinal measures with equal-appearing intervals (Likert) may be treated as interval/ratio measures 1 = Very Satisfied 2 = Satisfied 3 = Dissatisfied 4 = Very Dissatisfied
Validity Validity is about accuracy and whether the operationalization is correctly indicating what it's supposed to. Face Content Construct Criterion Concurrent Predictive
Reliability Validity is about accuracy and whether the operationalization is correctly indicating what it's supposed to. Test-retest Parallel form & inter-item Split-half (internal consistency) Inter-rater
Reliability & Validity Example 1: The High School Personality Questionnaire (HSPQ) is a self-report inventory for children ages It measures 14 personality characteristics that research has shown to be good predictors of social, clinical, occupational, and school behavior. Short-term test-retest reliability is in the.70s and.80s, and long-term is in the.50s and.60s. Factor analysis was used to establish construct validity. Test-retest reliability Construct validity
Reliability & Validity Example 2: The Goodenough-Harris/Draw a Person Test may be used to estimate developmental status in children from 5 to 17 years of age. Because it is a nonverbal measure of ability, it can be given to children from diverse cultures and to deaf children. Eleven raters with inter-rater reliability in the mid.90s assessed the sample. Internal consistence was estimated as being in the high.80s using Cronbach's Alpha. The average test-retest reliability coefficient was.74. The validity for the construct "developmental change" was established in the.60s which showed that scores tend to increase with age, as expected in any test of development. Inter-rater reliability Internal consistency (split-half) Test-retest reliability Construct validity