My Collection #1

Flashcards:
أهداف البحثFlashcardsPublic Unlisted
Diagram:
مخطط شجري لاتخاذ القرار في اختيار نوع الدراسة الطبية والصحيةDiagramPublic Unlisted
Flashcards:
أنواع الدراساتFlashcardsPublic Unlisted
Flashcards:
Medical ResearchFlashcardsPublic Unlisted
Diagram:
العلاقة الهيكلية بين مجتمعات البحث والعينة في البحوث الطبية (Population and Sample Hierarchy)DiagramPublic Unlisted
Flashcards:
أسرار اختيار عينات البحثFlashcardsPublic Unlisted
Flashcards:
أدلة المتغيرات البحثيةFlashcardsPublic Unlisted
Flashcards:
متغيرات البحث الطبيFlashcardsPublic Unlisted
Flashcards:
متغيرات البحث الطبيFlashcardsPublic Unlisted
Worksheet:
مصفوفة اتخاذ القرار لطرق جمع البيانات الطبيةWorksheetPublic Unlisted
Worksheet:
ورقة عمل تدريبية: تقييم جودة وصدق استبيانات البحث العلميWorksheetPublic Unlisted
Worksheet:
تقييم جودة وصلاحية استبيانات البحوث الصحيةWorksheetPublic Unlisted
Diagram:
الفرق بين الصدق والثبات في أدوات القياس البحثية (Validity vs. Reliability)DiagramPublic Unlisted
Diagram:
Comparison of Validity and Reliability in Research Measurement ToolsDiagramPublic Unlisted
Document:
في البحوث الطبية والصحية، يُمثل **الانحياز البحثي (Research Bias)** أي انحراف نظامي (Systematic Error) عن الحقيقة في تصميم الدراسة، أو جمع البيانات، أو تحليلها،
يقدم هذا الدليل استعراضاً شاملاً لأربعة من أبرز أنواع الانحياز في الدراسات الطبية، مع توضيح آليات حدوثها وتأثيراتها، وصياغة قائمة تحقق (Checklist) عملية للحد من
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الدليل العملي وقائمة التحقق لتحديد والحد من الانحياز في البحوث الطبيةDocumentPublic Unlisted

Flashcards:Medical Research

Medical Research

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Experimental Studies

An experimental study is a research design where the investigator actively intervenes by manipulating an independent variable and randomly assigning participants to groups to establish cause-and-effect relationships.

Involves direct researcher intervention, such as administering a new drug or treatment.
Random assignment (Randomization) is a core feature to eliminate confounding variables and ensure group comparability.
Considered the gold standard in medical and health research for proving causality.
Can be ethically challenging or impossible to implement when studying harmful exposures or rare conditions.

Observational Studies

An observational study is a research design where the investigator simply observes and records exposures and outcomes without making any intervention or manipulating variables.

No direct intervention or treatment is applied by the researcher; natural conditions are observed.
Essential for studying topics where experimental manipulation would be unethical, such as smoking or toxic exposures.
Subtypes include cohort studies, case-control studies, and cross-sectional studies.
More prone to confounding and bias compared to experimental studies, making it harder to prove direct causation.

Cohort Studies

A cohort study is an observational design that follows a group of people free of disease over time to see how exposure to certain factors affects the development of an outcome.

Can be prospective (following participants forward in time) or retrospective (looking at historical records).
Excellent for studying multiple outcomes related to a specific exposure and calculating incidence rates.
Mnemonic: Cohort = 'Company/Group marching forward together through time'.
Prone to high attrition rates (loss to follow-up) over long periods and requires large sample sizes for rare diseases.

Case-Control Studies

A case-control study is a retrospective observational design that compares people with a specific condition (cases) to those without it (controls) to identify past exposures.

Starts with the outcome (disease) and looks backward in time to determine the exposure.
Highly efficient and cost-effective for studying rare diseases or conditions with long latency periods.
Mnemonic: Cases have the Condition, looking Backward.
Highly vulnerable to recall bias because participants must accurately remember past exposures.

Cross-Sectional Studies

A cross-sectional study is an observational design that analyzes data from a population at a single specific point in time to assess prevalence.

Provides a snapshot of both exposure and outcome simultaneously without any follow-up period.
Fast, inexpensive, and useful for assessing disease prevalence and public health planning.
Mnemonic: Cross-section = A snapshot or X-ray slice in time.
Cannot establish temporal sequence or causality because exposure and outcome are measured at the same moment.

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Randomized Controlled Trials (RCTs)

A randomized controlled trial is an experimental study design where participants are randomly allocated to receive either an active intervention or a control/placebo.

Randomization ensures that known and unknown confounding variables are evenly distributed between groups.
Often double-blinded (neither participants nor researchers know who gets the treatment) to reduce bias.
Widely regarded as the highest level of evidence in clinical and health research.
Expensive, time-consuming, and strictly regulated by ethical boards and informed consent requirements.

Confounding Variables

A confounding variable is an extraneous factor that correlates with both the independent and dependent variables, falsely making it appear that a direct causal relationship exists.

Can distort research results if not properly identified, controlled, or adjusted for during analysis.
Common examples in health research include age, smoking status, and socioeconomic background.
Controlled in experimental studies via random assignment, and in observational studies via matching or multivariable regression.
Students often confuse confounding variables with mediating variables, but confounders distort the true relationship rather than acting as a causal bridge.

Recall Bias

Recall bias is a systematic error that occurs when participants in a study do not remember previous events or exposures accurately, often influenced by their current health status.

Particularly common in retrospective case-control studies where sick patients search their memories for causes of illness.
Patients with a serious disease tend to overreport past exposures compared to healthy controls.
Can be minimized by using objective medical records rather than self-reported questionnaires.
Often confused with selection bias, but recall bias specifically affects memory and data reporting accuracy.

Selection Bias

Selection bias is a systematic error introduced when the study population or the method of grouping participants is not truly representative of the target population.

Occurs during the enrollment or sampling phase when certain individuals are more likely to be included than others.
Includes examples like healthy worker effect or volunteer bias (where participants are more health-conscious than the general public).
Threatens the external validity (generalizability) of the research findings.
Minimised by using randomized sampling techniques and high response rates.

Causality vs. Association

Causality means that a change in one variable directly causes a change in another, whereas association simply means that two variables share a statistical relationship without proving cause.

Observational studies primarily establish statistical association or correlation, not definitive causation.
Experimental studies (like RCTs) are required to provide strong evidence of causality.
Mnemonic: 'Correlation does not equal causation' (e.g., ice cream sales correlate with drowning rates due to summer weather, not because ice cream causes drowning).
Common mistake is assuming that a strong correlation automatically implies that one factor causes the other.