This Presentation has been given to Dr.Raza Ullah in Methods of Social Rasearch by the students of UMT,Lahore

1. What is an Experiment?

2. • An experiment uses logic& symbol found in
Natural Sciences
• It is usually conducted in laboratories
• It usually involves less number of people
• It addresses well focused questions

3. • It is most effective for explanatory research
• The experimenter experiments a question
• The experimenter divides the population into
two groups

4. Before the upcoming elections ECP (Election
Commission of Pakistan)to check the new
system is fair or not used computerised system in
the by elections of two constituencies PP126 and
PP 143 and found that the system is fair.

5. What is a research?

6. Research is a collection of
methodology used
systematically to produce
knowledge about something.

8. What is experimental research?

9. • Experimental research is a research in which
we use logic & symbols found in natural
science
• An experiment means, “modifying something
in a situation, then comparing an outcome to
what existed without the modification”

10. • I try to start my car. To my surprise, it does not
start.
• I “experiment” by cleaning off the battery
connections, then try to start it again.
• I modified something(cleaned the connections)
and compared the outcome (weather the car
started) to previous situation (It didn’t start).

11. I drew the hypothesis
• Once the terminals is cleaned off the car will
start.

12. This illustrates three things researchers do in
experimental research:
• Begin with a hypothesis
• Modify something in a situation
• Compare outcomes with and without the
modification

13. Research questions appropriate for
experimental research

14. • New researchers often asks which research
techniques best fits which problem
• It is difficult answer these questions because
there is no fixed match between problem and
technique

15. The answer is:
• Make an informed judgment.
• You can develop the judgment by:
• reading research reports
• understanding the strengths & weakness of different techniques
• Assisting more experiences researches with their research training
• Practical Experience

16. What is Random assignment?

17. • Random assignment is a method for assigning cases (e.g.,
individuals, organizations, etc.) to groups for the purpose of
making comparisons.
• It is a way to divide a collection of cases into two or more
groups in order to increase ones confidence that the groups do
not differ in a systematic way.
• It is a mechanical method; the assignment is automatic, and
the researchers cannot assignments on the basis of personnel
preference or the features of specific cases.

18. • Random assignment is random in statistical or
mathematical sense.
• Random selection lets researcher calculate the
odds that a specific case will be sorted into one
group over another.
• For example, A researcher wants to research the
IQ level between the ages 20, 30,50. he randomly
makes the group of 50 each

19. What are subjects?

20. The names of participants in experimental
research
Cases and people used in research project and on
whom variables are measured

21. Dependent
Variable
Random Pretest
Assignment
Treatment or
Independent
variable
Control
Group Posttest
Experimental
Group
Parts of Experiments

22. There are seven Parts of Experiments
• Treatment or Independent variable
• Dependent variable
• Pretest
• Posttest
• Experimental group
• Control group
• Random Assignment

23. What is treatment or Independent
Variable?

24. • Treatment (stimulus or manipulation) is what a
researcher modifies.
• In most experiments, a researcher creates a
situation and then modifies it.
• The term originated from the discipline of
medicine in which a physician treats a patient.

25. • On such pattern a researcher develops a
measuring instrument or indicator
• Example; (Survey questions),then apply it to a
person or a case.
• In experiment researcher “measure” independent
variable by creating a situation

26. • For example; the independent variable is
degree of fear or anxiety”, the levels are high
fear and low fear.
• Instead of asking subject weather they are
fearful the experimenters puts subjects into
high fear or low fear.
• They measure the independent variable by
manipulating conditions so that some subjects
feels lots of fear and others feel little

27. What is dependent variable?

28. • Dependent variable or outcomes in
experimental research are the physical
conditions, social behaviors, attitudes, feeling,
or beliefs of subjects that change in response to
a treatment.
• Dependents variables can be measured by
paper-and-pencil indicators, observations,
interviews, or physiological responses(e.g.,
heart attack and spreading pain)

29. What is Pretest?

30. • The pretest is the measurement of the
dependent variable prior to the introduction
of the treatment(e.g.; anxiety and ulcer)

31. What is Posttest?

32. • The posttest is the measurement of the
dependent variable after treatment has been
introduced into experimental group (e.g.,
children of divorcee’s have high rate of
angriness while children of married couples
have low rate of angriness)
• Mostly experimental researchers divides
subjects into two groups

33. What is Experimental Group?

34. • The group that receives the treatment or in
which treatment is present.(e.g.,
questionnaires) is a treatment usually used as
indicator and usually applied to a group in a
certain condition.

35. What is Control group?

36. • The group that does not receive the treatment
is called the control group.
• When the independent variable takes on
many different values, more than one group

37. Steps in Conducting an Experiment

38. • Begin with a straightforward hypothesis that is
appropriate for experimental research
• Decide on an experimental design that will
test the hypothesis within practical limitations
• Decide how to introduce a treatment or create
a situation that induces the independent
variable

39. • Develop a valid and reliable measure of the
dependent variable.
• Set up an experimental setting and conduct a
pilot test of the treatment and dependent
variable measures.
• Locate appropriate subjects or cases.

40. • Randomly assign subjects to groups (if random
assignment is used in the chosen research
design) and give careful instructions.
• Gather data for the pretest measure of the
dependent variable for all groups (if a pretest is
used in the chosen design)

41. • Introduce the treatment to the experimental
group only (or to relevant groups if there are
multiple experimental groups) and moniter all
groups
• Gather data for posttest measure of the
dependent variable

42. • Debrief the subjects by informing them of the
true purpose and reasons for the experiments.
Ask subjects what they thought was occuring.
Debriefing is crucial when subjects have been
deceived about some aspect of the experiment.

43. • Examine data collected and make comparisons
between different groups. Where appropriate,
use statistics and graphs to determine wether
the hypothesis is supported

44. Types of Experiments

45. • Classical Experimental Design
• Pre experimental design
• One-Shot Case-Study Design
• One Group Pretest-Posttest Design
• Static Group Comparison
• Qausi-Experimental and Special Designs

46. • Two-Group Posttest-Only Design
• Interrupted Time Series
• Equivalent Time Series
• Latin Square Designs
• Solomon Four-Group Design
• Factorial Designs

47. • Interaction effects

48. What is classical Experimental
design?

49. • An experimental design that has random
assignment, a control group, an experimental
group, and a pretest and posttest for each
group.

50. • For Example; The experimenter gives 40
newly hired wait staff an identical two-hour
training session and instructs them to follow a
script in which they are not to introduce
themselves by first name and not to return
during the meal to check on the customers.

51. • The experimenter divides them into two equal
groups of 20 randomly.
• The experimenter records the amount of tips of
all the subjects for a month (pretest).
• The experimenter retains the group 1 at
resturant 1 (experimental Group)
• The experimenters asks them to introduce
themselves by first name for 8mins (treatment)

52. • The group 2 continue their work without an
introduction or checking during the
meal(control group)
• Over the second month the amount of tips for
both groups is recorded (posttest)

53. What is Pre experimental Designs?

54. • Experimental design that that lack randonm
assignment or use shortcuts and are much
weaker than the classical experimental design.
They are be substituted in situations in which
an experimenter cannot use all the features of a
classical experimental design, but have weaker
internal validity

55. What is one-Shot Case-Study?

56. • An experimental design with only an
experimental group and a posttest

57. What is static group Comparison
Design?

58. • An experimental Groups with two groups, no
random assignment and only a posttest

59. What is Quasi Experimental and
Special Designs?

60. • Experimental designs that are stronger than pre
experimental designs. They are variations on
the classical experimental design and are used
in special situations or when an experimenter
has limited control over independent variable

61. What is two-Group Posttest-Only
Design?

62. • This is identical to the static group
comparison, with one exception: The groups
are randomly assigned. It has all the parts of
the classical design except a pretest. The
random assignment reduces the chance that the
groups differed before the treatment, but
without a pretest, a researcher cannot be as
certain that the groups began the same an the
independent variable.

63. What is an interrupted time-series
design?

64. • An experimental design in which the
dependent variable is measured periodically
across many time points, and the treatment
occurs in the midest of such measures, often
only once.
e.g.: anxiety and depression test over an anxiety
patient and its treatment.

65. What is an Equivalent
time series Design?

66. • An experimental design in which there are
several repeated pretests, posttests, and
treatments for one group often over a period of
time.
• Example; the experimenter experiments that
the people who do not wear helmets can have
swear head injury. The bill was passed on 1975
repelled in 1981 and reinstated in 1998.

67. What is Latin Square design?

68. • An experimental design used to examne
whether the order or sequence in which
subjects receive multiple versions of the
treatment has an effect
• Example; A geography teacher has three units
to teach students: map reading, using a
compass, LL system (longitudinal and
latitudinal system )

69. • In one class he used one method and in second
class he used in another class and in class three
he used both system in the end he took end test
to check weather the learning environment
improved or not.

70. What is Solomon four-Group
design?

71. • An experimental design in which subjects are
randomly assigned to two control groups and
two experimental groups. Only one
experimental group and one control group
receive a pretest. All four Groups receive a
posttest.

72. • Example; A mental health worker want to
determine whether a new training method
improves clients’ copying skills. the worker
measures coping skills with a 20 minutes test
of reactions to stressful evens. Because the
clients might learn coping skills from taking
the test itself, a Solomon four-group design is
used.

73. • The mental health worker divides the clients
into four groups.
• Two groups receive pretest. One of them gets
new training method an the other gets old
training method. Another two groups receive
no pretest.
• All four groups are given the same posttest and
posttest results are compared.

74. What are Factorial designs?

75. • A type of experimental design that considers
the impact of several independent variables
simultaneously.

76. What is an interaction effect?

77. • An effect of two independent variables
operating simultaneously and in combination
on a dependent variable. It is a larger effect
than occurs from the sum of each independent
variable working separately

78. Internal Validity
External validity
What is Internal and external
validity?

79. Internal Validity
• The ability of experimenters to strengthen the
logical rigor f a casual explanation by
eliminating potential alternative explanations
for an association between the treatment and
dependent variable through an experimental
design
• Variables other than the treatment that effects
the dependent variable are threats to internal
validity.

80. External Validity
• The ability to generalize the findings beyond a
specific study

81. What are Field Experiments?

82. • A field experiment applies the scientific method to experimentally
examine an intervention in the real world (or as many
experimentalists like to say, naturally occurring environments)
rather than in the laboratory. Field experiments, like lab
experiments, generally randomize subjects (or other sampling units)
into treatment and control groups and compare outcomes between
these groups.
• Examples include:
• Clinical trials of pharmaceuticals are one example of field
experiments.
• Economists have used field experiments to analyze discrimination,
health care programs, charitable fundraising, education, information
aggregation in markets, and microfinance programs.
• Engineers often conduct field tests of prototype products to validate
earlier laboratory tests and to obtain broader feedback.