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• Mediation Analysis as a method to connect the causal-effect relation in being used popularly in Medical writing for clinical research, especially since the last decade. • The type of Mediation Analysis model is dependent on the needs of the study and each has its own set of advantages and disadvantages. Full Information: https://bit.ly/3hdJCYa Reference: https://pubrica.com/services/research-services/ Why pubrica? When you order our services, we promise you the following – Plagiarism free, always on Time, outstanding customer support, written to Standard, Unlimited Revisions support and High-quality Subject Matter Experts. Contact us : Web: https://pubrica.com/ Blog: https://pubrica.com/academy/ Email: sales@pubrica.com WhatsApp : +91 9884350006 United Kingdom: +44-74248 10299
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Copyright © 2020 pubrica. All rights reserved 1
Classification of Mediation Analysis Methodology in Clinical Research
Dr. Nancy Agens, Head,
Technical Operations, Pubrica
sales@pubrica.com
In Brief
Mediation Analysis as a method to
connect the causal-effect relation in
being used popularly in Medical writing
for clinical research, specially since the
last decade. The type of Mediation
Analysis model is dependent on the needs
of the study and each has its own set of
advantages and disadvantages. Since
there is significant heterogeneity in the
manner it is used, there is need for
methodological uniformity.
Keywords
Scientific Medical Writing Companies,
Medical Writing In Clinical Research,
scientific research paper writing, Medical
Writing for Clinical Trials, Medical
Writing in Clinical Trials, Clinical
Research Services, Medical Writing CRO,
research paper writing service, Medical
Writing for Clinical research, research
paper writing help, Scientific Writing
Help, clinical medicine research, medical
research companies.
I. WHAT IS MEDIATION ANALYSIS
Mediation analysis (MA) is a form
of statistical analysis and is very
commonly used in epidemiology,
psychology, sociology, and medicine by
Scientific Medical Writing Companies. It
attempts to predict the relation between the
antecedent variable and the outcome
variable by Clinical Research Services. In
other words, Medical Writing in Clinical
Research use MAto try and find
methodology by which outcome is related
to exposure.Thus, it is useful in both
interventional and observational studies
while scientific research paper writing or
Medical Writing for Clinical Trials.
Research paper writing help use mediation
model as a causal model where mediator is
presumed to cause the effect, while the
vice versa is not true. So, wherever the
presumption is not correct, MA is not
useful. Statistics is used to evaluate
whether the presumption of the MA is
correct or not.
Scientific writing help use this
information while research paper writing
and it is useful to find the association with
causation. This helps understand the
disease aetiology better and this
information is used to improve or alter
existing treatment and management
modality.
II. CLASSIFICATION OF MEDIATION
ANALYSIS METHODOLOGY
There following are the methods used in
MA:
1. Traditional approaches Single
measure: - In this method, separate
regression models are used for the
antecedent and the outcome variable in
clinical medical research. E.g. Baron
and Kenny’s framework is commonly
used by Medical Research Companies.
X is the causal variable and Y is the
outcome in the absence of any
mediation as per the below
representation. Path C is the total
effect.
Mediating variable M in the below
figure is the process or intervention
Copyright © 2020 pubrica. All rights reserved 2
variable. Path C´ in this figure is the
direct effect. When the path from X to
Y is reduced but above zero, there is
partial mediation, while when C´
becomes zero, there is complete
mediation.
There are four steps in the Baron and
Kenny’s model in establishing
mediation.
Step 1: - To show that the antecedent
variable correlates with the outcome
variable.
Step 2: - To show that the antecedent
variable correlates with the mediator.
Step 3: - To show that the mediator
affects the outcome variable.
Step 4: - To establish that the mediator
completely mediates the causal- effect
relationship.
Total effect = direct effect + indirect
effect OR
C = C´ + ab
Complete mediation is proved when all
the four steps are met, while partial
mediation is indicated if Step 4 is not
met.
2. Counterfactual approaches Single
mediator: - Lewis’s 1973
counterfactual analysis is based on the
understanding that, if an antecedent
event is the complete causal factor for
the effect, then, there would not be the
effect if there is no antecedent event.
Medical Writing CRO use different
regression models for the antecedent
and the outcome. Causal contrast is
highlighted between the exposed and
the non-exposed.
In the causal-effect model, when
there are multiple mediators that need to
be evaluated, one can consider one
mediator at a time. This is possible only
when mediators do not affect each other.
However, if we need to evaluate several
mediators simultaneously or in cases
where mediators affect each other, we
need to use either parallel or serial MA.
Mediation with single mediator M, A is
exposure, Y is the outcome and C is the
confounder.
Mediation with two mediators M(1)
, M(2)
,
A is exposure, Y is outcome and C is the
confounder.
Mediators with unknown common cause,
where mediators do not affect each other.
Copyright © 2020 pubrica. All rights reserved 2
Mediators with unknown common cause,
where mediators affect each other.
3. Parallel mediators: Medical Writing for
Clinical research uses parallel multiple
mediators that need to be evaluated at
the same time. Regression model is
used for all mediators and separate
models are used for different
mediators.
4. Serial or sequential Mediation: - Serial
mediation is used when mediators act
one after the other for the outcome or
the chain reaction.
An example of a sequential MA is a
survey study conducted on Chinese
university students linking indicators
of career adaptability in the context of
changing job scenario and challenges
faced by Chinese university students
while seeking jobs or building their
careers.
III. FUTURE SCOPES
MA is based on strong assumptions
that need to be discussed to avoid
misinterpretations. Planning MA in
advance is preferred as it helps in adjusting
in the methodologies to account for
appropriate sample size, key confounders,
and measurement errors in mediators.
There is considerable heterogeneity in the
planning, conduct and reporting of MA,
necessitating the need to have uniform and
consensus-based guidelines on the
methodology.
IV. CONCLUSION
MA is a statistical technique which
is being used increasingly by Research
Paper Writing Services and Medical
Writing in Clinical Trials. There is no
single approach to MA, researchers may or
may not have a prior hypothesis. Scientific
research writing help may focus on direct
or indirect antecedent causal evidence or
association-based studies. Each model of
MA has its own advantages and
disadvantages and the model chosen
depends on the type of study.
REFERENCES
1. MacKinnon, D. R., Kisbu-Sakarya, Y., &
Gottschall, A. C. (2013). Developments in
mediation analysis. In T. D. Little (Ed.), Oxford
library of psychology. The Oxford handbook of
quantitative methods: Statistical analysis (p. 338–
360). Oxford University Press.
2. VanderWeele, T. J., & Vansteelandt, S. (2014).
Mediation Analysis with Multiple
Mediators. Epidemiologic methods, 2(1), 95–115.
3. Zhuang Mingke, She Zhuolin, Cai Zijun, Huang
Zheng, Xiang Qian, Wang Ping, Zhu Fei (2018).
Examining a Sequential Mediation Model of
Chinese University Students’ Well-Being: A Career
Construction Perspective. Frontiers in Psychology,
9, 593.
4. Tat-Thang Vo,Cecilia Superchi,Isabelle
Boutron,Stijn Vansteelandt (2020). The conduct and
reporting of mediation analysis in recently
published randomized controlled trials: results from
a methodological systematic review. Journal of
Clinical Epidemiology,117,78-88.
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