analytical studys Flashcards
(16 cards)
What is the ourpose of an analytical study
to test hypotheses
What are the key concepts of an analytical study
Replicability - to ensure that true effects aren’t masked by chance events
Control - context to the effects of interest
What are the benifits of an experimental study
- reserches can manipulate conditions
- control all factors other than tested one
- best at studing causation
- randomisation used to ensure equal distribution of random variables
What are the two kinds of analytical studys and subtypes of these classes
Experimental
- randomized control study
Observational
- cohort study
- case controled study
what are the main factors of a randomised control study
requires randomisation to create 2 compairable groups
blinding to ensure no bias between contol and drug
placebo for the control
What are the advantages and disadvantages o a randomised control study
Advantages:
- best way to test a hypothesis
- well done trials can associate the control with the causation
Disadvantages:
- can be unethical or impracticale
What are the factors of an observational study
- no intervention from the investigator
- as close as posible to experimental
What are the factors of a case controled study
- two groups are collected with or without the change of interest
- information is gained from the past
What are the advantages and disadvantages of a case controled study
advantages:
- relatively quick
- smaller sample size (as can select for people with a rare disease)
- can test multiple conditions
Disadvantages:
- hard to eliminate all confoudning
- recall biase due to talking about inforrmation from the past
What are the factors of a cohort study
participants are gathered and split themselves into two groups
- selection before disease has manifested and followed overtime
- has a non-random control group
what are the advantages and disadvantages of cohort studys
Advantages:
- closest to experimental
- good for common outcomes
- can study multiple conditions
Disadvanages:
- hard to eliminate confounding problems
- long duration required
- rare disease requires LARGE sample sizes
What do we need to do when making a hypothesis
Make it precise
Specify timeline, quanititys, population
what is the aim of an interventional study
The aim is to quantify the impact of the intervention on the outcome of interest
What is confoundance
Confoundance is when a third variable which has an effect on both the outcome and the control without going through the causal pathwayu
What is the causal pathway
The string of events leading from the intervention to change the outcome of interest
What is the difference between information bias and selection bias
both systematic
Selection bias: The bias produced from poor subject selecion, causes differences between the two groups
Information bias: The bias caused from errors with data collection, interpretation, or recording
- observer, subject, tools, missed measurements
