Chapter 3
How we study children and adolescents
 The Scientific Method
 Ethics in Research With Children and
Adolescents
 Finding and Assessing Information About
Development
Basic and Applied Research
 Basic research
primary goal of adding to our body of
knowledge rather than having immediate,
direct application
 Applied research
primary goal of solving problems or
improving the human condition
The Scientific Method
 Developing Hypotheses
 Operationalizing Concepts
 Sampling and Representative Samples
 Methods and Measures
 How Research Is Designed
 Interpreting the Results of a Study
Developing hypotheses
Hypothesis: A prediction, often based upon
theoretical ideas or observations, that is
tested by the scientific method.
Operationalizing concepts
Operationalization: Defining a concept in a way
that allows it to be measured.
Reliability and validity
 Reliability: The ability of a measure to
produce consistent results.
 Validity: The ability of a measure to
accurately measure what it purports to
Sampling and Representative Samples
A population = everyone in the category we are
interested in studying or learning more
about.
BUT…usually we cannot study an entire
population, so
a sample of a population is selected to reflect
the characteristics of the population of
interest, called a representative sample
How do we measure the
concepts/variables we want to study?
 Observations
 Self-report measures: surveys,
questionnaires, interviews
 Standardized tests
 Archival records
 Physiological measures
 Experiments
 Case studies
How research is designed:
Experimental design
 Random assignments of participants to
 Experimental group – gets the “treatment”
 Control group – does not get the “treatment”
 The “treatment” is the independent variable
 The outcome is the dependent variable
How research is designed: Natural or
quasi-experiments
 Comparing groups that receive different
“treatments”, but these “treatments” were
not set up by the experimenter.
How research is designed: Correlational
design
There is no “treatment” assigned to different
groups. The researcher examines whether
variables that occur naturally are related to
one another.
Therefore, causality cannot be inferred between
variables.
Direction of Correlations
Strength of Correlations
Developmental research designs
 Longitudinal research
6-year-olds are tested again at age 8.
 Cross-sectional research
6-year-olds and 8-year-olds are tested at the
same time.
 Cross-sequential research
6-year-olds and 8-year-olds are tested at the
same time and then again 2 years later at
ages 8 and 10.
Interpretation of Results
 Don’t generalize results to populations
not found in the representative sample
 Understand that most results are
“averages” and won’t apply to every
individual.
 Statistical significance implies that the
results were not found by chance. It
doesn’t mean the results are of great
practical significance
Be wary of the results of one individual study.
Results need to be replicated in numerous
studies
Ethics in research with children and
adolescents
 Minimum risks
 Informed consent of parent and child
 Right to withdraw from research
 Confidentiality of information
Finding and assessing information
 Good sources of information:
 Library databases: PsycINFO, ERIC
 Peer-reviewed journals
 Carefully evaluate information on the
internet
Web information
 The case of the Pacific Northwest Tree
Octopus
 How would you decide whether this website
has legitimate information?
 http://zapatopi.net/treeoctopus/