1) There are two basic types of experimental research designs: randomized controlled trials and quasi-experimental designs. Randomized controlled trials are considered the gold standard as randomization makes treatment groups comparable. 2) There are four main types of observational studies: cohort studies, case-control studies, cross-sectional surveys, and case reports. Cohort studies follow groups over time from exposure to outcome while case-control studies work backwards from an outcome to exposures. 3) Experimental and observational studies both have strengths and weaknesses for evaluating causes and effects in health research. The strongest evidence comes from systematic reviews and meta-analyses of multiple studies.

1. RESEARCH ,METHODS IN
HEALTH PSYCHOLOGY

2. Introduction to
healthcare research
International Clinical Trials Day
is celebrated on the 20th May
each year to commemorate
the day that James Lind
started his important trial on
scurvy. The day aims to
highlight research in
healthcare and how vital it is
in the delivery of high-quality
medical practice.
Curing all ship members by giving them citrus fruits

3. Why carry out research within healthcare?
 Evidence suggests that patients who receive care in research-active hospitals
have better health outcomes. This is due to the research-active hospital being
able to offer wider treatment options and more opportunities to be included in
clinical trials.
 Patients taking part in clinical trials also have tend to have increased time with
the clinical team members. Therefore problems are likely to be identified
sooner. Taking part in research can help patients gain a better understanding
of their condition and management.

4. In the early 1900’s
there was much investigation of the
role of vitamins on the human body.
The British Physician, Sir Edward
Mellanby (1884 – 1955), in 1916
discovered how increasing Vitamin D
in the diet could cure rickets.

12. Conducting research in Health Psychology
Like psychologists in the other main psychology disciplines, health psychologists
have advanced knowledge of research methods. Health psychologists apply this
knowledge to conduct research on a variety of questions.
For example, health psychologists carry out research to answer questions such as:
 What influences healthy eating?
 How is stress linked to heart disease?
 What are the emotional effects of genetic testing?
 How can we change people’s health behaviour to improve their
health?

13. Much research in health psychology is
experimental.
 In an experiment, a researcher creates two
or more conditions that differ from each
other in exact and predetermined ways.
 People are then randomly assigned to
these different conditions, and their
reactions are measured.
 Experiments conducted by health care
practitioners to evaluate treatments or
interventions and their effectiveness over
time are also called randomized clinical
trials, in which a target treatment is
compared against the existing standard of
care or a placebo control.

14. Studies where the primary objective is to
evaluate the relationship between a cause
and an effect, an exposure (a risk factor or
a protective factor) and a disease, or an
outcome, are called analytical studies.
Observational Studies
A study is observational
when the natural
course of events is
monitored without any
intervention
Experimental Studies
random group assignments
to measure the effect of an
independent variable (e.g.
how it influences behaviour).
1. Randomized controlled trials
2. Quasi-experimental designs.
1. Cohort Studies,
2. Case-control Studies
3. Cross-sectional Surveys,
4. Case Reports

15. 1) There are two basic types of experimental research
There are two basic types:
1. Randomized controlled trials and
2. quasi-experimental designs.
"Randomized controlled trials“
• are considered the gold standard of medical evidence,
They are designed to tease out cause-and-effect relationships; randomization means
treatment groups are comparable, and the only difference between them is the intervention (i.e.,
whether they received the drug or not) so any difference in outcome between the two groups
can be attributed to the intervention.
• When these experiments are blinded, they're even more powerful: blinding means either the
study participants, the doctors, or both ("double-blinded") do not know whether they are
receiving/giving the real treatment or a placebo. So blinded studies account for any placebo
effects that may arise.

16. There's a type of study design that lies
somewhere between experimental and
observational research:
that's the "quasi-experiment.“
These are essentially a type of unplanned or
uncontrolled experiment that uses statistics
and human ingenuity to mimic the conditions
of an experiment. Scientists have found many
ways of undertaking these. One example

17. 2) There are four basic types of observational studies
There are many different types of observational studies,
but here are the four most common that you need to
know about:
 Cohort Studies / Prospective
 Case-control Studies / Retrospective
 Cross-sectional Surveys,
 Case Reports.

18. (Cause to effect)
(effect to cause)

20. (Prospective)

22. Case-control studies" are often called "retrospective
studies." That's because researchers start with an end point
and work backward, figuring out what might have caused
that outcome.
For example, researchers could take two groups of people
who live in Washington, DC: those who have been
diagnosed with heart disease and those who haven't.
They could then work backwards and survey the two
groups about their earlier health behaviours to figure
out what might have caused the disease to develop or
not. They may ask about saturated fat consumption or
exposure to disease-inducing viruses. From there, they
would note any differences in risk factors or exposures that
emerge between the two groups which can help suggest
what may have led to heart disease in some people.

24. "Case reports" are basically detailed stories about a
particular patient's medical history. If a doctor writes up
case reports about a cluster of patients with the same
condition or disease, this is a "case series." Though these
are considered the weakest kind of observational studies,
they can still be very helpful for rare diseases and
powerful for advocacy. Sometimes they can be a bellwether
in medicine. Early case reports, for example, led to the tragic
discovery that mothers who were taking thalidomide for
morning sickness were having babies with missing limbs.
These reports surfaced long before a randomized trial could
ever be done — and spared thousands. of babies.

25. (Prospective)
(Retrospective)

26. The classical hierarchy of evidence.
The king of all evidence:
Systematic Reviews
Researchers often rank study
designs in hierarchies to describe
the relative weight of their
conclusions.