PYC3704 – PSYCHOLOGICAL RESEARCH
TOPIC 1 – QUANTITATIVE METHODS IN RESEARCH PSYCHOLOGY
Quantitative Research in Psychology:
Psychology is a discipline that endeavours to collect information and develop theories about
human behaviour and mental processes
All scientific knowledge begins with description of the phenomena being studied, based on
careful observation
o Knowledge based on observation of physical events is referred to as empirical
knowledge
o The next step in the scientific process is to go beyond the level of description by
attempting to develop explanations for the things we observe: we want to know not
only what the facts are, but also why they appear to be as they are
In other words, we want to develop theories, which explain why things are as
they appear to be when we observe them
Quantitative methods refer to situations where information (referred to as data) is available
as numbers, which are the consequences of measurements of some kind
o Statistics refer to the study of probabilities, which becomes relevant when we deal
with data that are imperfect or incomplete, data that contain measurement error
o An inference – a conclusion that follows from existing information, by generalising
from the specific information to the general type of phenomenon, where the
conclusion isn’t absolutely certain
Constructs as the Building Blocks of Theories:
Constructs:
Psychologists try to develop explanations for human experiences and behaviour
o To do this, they often have to make use of abstract concepts that serve as
explanations for the behaviour they observe
Theories:
Psychologists are interested to find out which constructs are important and how they work
together in a pattern, or what their interrelationships are
Constructs are the building blocks of theory
In science, a theory is a framework for facts
Constructs and their interrelations are used in this way to develop theoretical explanations
of why people behave in certain ways in certain contexts, or why mental phenomena
appear to be as they are
How Constructs are Made Visible Through Measurement:
Measurement:
Anything that can be differentiated in terms of type or amount can be measured
Quantification becomes relevant when we ask not only what the construct is that is in force
in the situation, but also to what extent it appears – that is, how much of it exists, or to what
intensity it exists
In psychological research, quantification depends on our ability to operationalise the
particular construct
o This refers to that fact that we have to devise a systematic procedure or operation to
make the construct visible, in such a way that we can measure it
Measurement refers to a process whereby numbers are allocated to something according
to a rule
, The link between observing a construct and measuring it is so close that when we talk
about ‘observation’ in quantitative research, we often imply the process of measurement
o The taking of a measurement is regarded as an act of observation
Because of this link between measurement and construct, the procedure of
operationalisation can also be said to provide an operational definition of a construct, as it
can be seen as a practical demonstration of what the construct is
The subdiscipline that deals with psychological measurement is psychometrics
o This discipline is concerned with issues such as the validity of measurements and
their reliability
Something one should always be aware of when considering measurements is the level of
measurement
We distinguish between 2 kinds of measurement
o Measurements where the quantity or intensity of some construct is considered which
we refer to as a quantity or measurement of intensity
o We use measurements that indicate category membership
Variables:
A construct that has been measured in some way produces a variable
A variable refers to a number that can take on any one of a range of possible values
They can be discrete or continuous
Variables can be contrasted with constants, which are numbers that can only take on a
single size
To the visible variable reflects the intensity of the underlying (invisible) construct, in terms of
how it was measured
o We say that the variable is manifest (it is visible in the sense that we can observe it)
and the construct is latent (it is invisible in the sense that we need some way to
make it appear)
When researchers refer to the interaction of specific variables, you have to keep in mind
that when they refer to how variables interact, they are really interested in the interaction of
the underlying constructs
One important distinction that we often need to make when we study the interaction among
variables, is the distinction between the dependent and the independent variable
o When a researcher focuses on the interaction of only 2 variables at a time, the
dependent variable is usually the 1 that the researcher is interested in, the variable
that is the focus of the research
o The independent variable is something that the researcher manipulates, to see how
this affects the dependent variable
o When there are only 2 variables involved, we often indicate the dependent variable
with a y and the independent variable with an x
Something else to keep in mind, even when we consider 2 variables only, is the possible
effect of hidden variables
o Hidden variables are effects on the dependent variable that may be unaware of, or
that we choose to ignore
o Very often the events or behaviour that we observed are the consequence of many
interacting factors, and we have to analyse the situation carefully to try and identify
as many things as possible that may interfere with our ability to find a clear
relationship between a dependent variable and some specific independent variable
Techniques of statistical inference can show you that a difference exists, but it cannot tell
you why it exists
Collecting Information by Sampling Data:
Data:
Refers to the collected information
TOPIC 1 – QUANTITATIVE METHODS IN RESEARCH PSYCHOLOGY
Quantitative Research in Psychology:
Psychology is a discipline that endeavours to collect information and develop theories about
human behaviour and mental processes
All scientific knowledge begins with description of the phenomena being studied, based on
careful observation
o Knowledge based on observation of physical events is referred to as empirical
knowledge
o The next step in the scientific process is to go beyond the level of description by
attempting to develop explanations for the things we observe: we want to know not
only what the facts are, but also why they appear to be as they are
In other words, we want to develop theories, which explain why things are as
they appear to be when we observe them
Quantitative methods refer to situations where information (referred to as data) is available
as numbers, which are the consequences of measurements of some kind
o Statistics refer to the study of probabilities, which becomes relevant when we deal
with data that are imperfect or incomplete, data that contain measurement error
o An inference – a conclusion that follows from existing information, by generalising
from the specific information to the general type of phenomenon, where the
conclusion isn’t absolutely certain
Constructs as the Building Blocks of Theories:
Constructs:
Psychologists try to develop explanations for human experiences and behaviour
o To do this, they often have to make use of abstract concepts that serve as
explanations for the behaviour they observe
Theories:
Psychologists are interested to find out which constructs are important and how they work
together in a pattern, or what their interrelationships are
Constructs are the building blocks of theory
In science, a theory is a framework for facts
Constructs and their interrelations are used in this way to develop theoretical explanations
of why people behave in certain ways in certain contexts, or why mental phenomena
appear to be as they are
How Constructs are Made Visible Through Measurement:
Measurement:
Anything that can be differentiated in terms of type or amount can be measured
Quantification becomes relevant when we ask not only what the construct is that is in force
in the situation, but also to what extent it appears – that is, how much of it exists, or to what
intensity it exists
In psychological research, quantification depends on our ability to operationalise the
particular construct
o This refers to that fact that we have to devise a systematic procedure or operation to
make the construct visible, in such a way that we can measure it
Measurement refers to a process whereby numbers are allocated to something according
to a rule
, The link between observing a construct and measuring it is so close that when we talk
about ‘observation’ in quantitative research, we often imply the process of measurement
o The taking of a measurement is regarded as an act of observation
Because of this link between measurement and construct, the procedure of
operationalisation can also be said to provide an operational definition of a construct, as it
can be seen as a practical demonstration of what the construct is
The subdiscipline that deals with psychological measurement is psychometrics
o This discipline is concerned with issues such as the validity of measurements and
their reliability
Something one should always be aware of when considering measurements is the level of
measurement
We distinguish between 2 kinds of measurement
o Measurements where the quantity or intensity of some construct is considered which
we refer to as a quantity or measurement of intensity
o We use measurements that indicate category membership
Variables:
A construct that has been measured in some way produces a variable
A variable refers to a number that can take on any one of a range of possible values
They can be discrete or continuous
Variables can be contrasted with constants, which are numbers that can only take on a
single size
To the visible variable reflects the intensity of the underlying (invisible) construct, in terms of
how it was measured
o We say that the variable is manifest (it is visible in the sense that we can observe it)
and the construct is latent (it is invisible in the sense that we need some way to
make it appear)
When researchers refer to the interaction of specific variables, you have to keep in mind
that when they refer to how variables interact, they are really interested in the interaction of
the underlying constructs
One important distinction that we often need to make when we study the interaction among
variables, is the distinction between the dependent and the independent variable
o When a researcher focuses on the interaction of only 2 variables at a time, the
dependent variable is usually the 1 that the researcher is interested in, the variable
that is the focus of the research
o The independent variable is something that the researcher manipulates, to see how
this affects the dependent variable
o When there are only 2 variables involved, we often indicate the dependent variable
with a y and the independent variable with an x
Something else to keep in mind, even when we consider 2 variables only, is the possible
effect of hidden variables
o Hidden variables are effects on the dependent variable that may be unaware of, or
that we choose to ignore
o Very often the events or behaviour that we observed are the consequence of many
interacting factors, and we have to analyse the situation carefully to try and identify
as many things as possible that may interfere with our ability to find a clear
relationship between a dependent variable and some specific independent variable
Techniques of statistical inference can show you that a difference exists, but it cannot tell
you why it exists
Collecting Information by Sampling Data:
Data:
Refers to the collected information
