RESS Term 1 Lectures

Question 1

What is evidence based medicine?

Answer 1

The conscientious use of current best evidence in making decisions about patient care

Question 2

What is a research question?

Answer 2

A question that directs and focuses your research

Question 3

What is an acronym that can help you develop a research question?

Answer 3

PICOT
Patients/Population - who will be participating?
Interest - what is being tested?
Comparison - what is the comparison group?
Outcome - what is the outcome or endpoint?
Time - when should outcome be measured?

Question 4

What is a non-randomised control trial?

Answer 4

An ‘uncontrolled’ study - no control group

Question 5

What are the strengths of Randomised Clinical Trials? (RCTs)

Answer 5

• provide evidence of causality- more chance of having ‘impact’
• rigorous evaluation of a single variable

Question 6

What are the limitations of Randomised Clinical Trials? (RCTs)

Answer 6

• resource intensive: costs, time and money
• needs a large number of participants- many studies underpowered
• ethical challenges

Question 7

What is a cohort study?

Answer 7

Cohort studies are a type of medical research used to investigate the causes of disease and to establish links between risk factors and health outcomes

Question 8

What are the strengths of cohort studies?

Answer 8

• can establish population-based incidence
• can study several outcomes for each exposure
• can establish cause-effect

Question 9

What are the limitations of cohort studies?

Answer 9

• resource intensive: costs time and money
• needs a large number of participants
• loss to follow up
• inefficient for rare conditions

Question 10

What is a cross-sectional study?

Answer 10

A document health status in a specific population at a specific point
Provides a snapshot, patients not followed

Question 11

What are the strengths of cross sectional studies?

Answer 11

• Provides estimates of prevalence of a disease
• Can identify population healthcare needs
• Easy, fast and inexpensive
• No follow-up required

Question 12

What are the weaknesses of cross sectional studies?

Answer 12

• Cannot determine causal relationships
• Participants may provide socially desirable answers
• Impractical for studying rare diseases

Question 13

What are the strengths of qualitative studies?

Answer 13

• Enables an understanding of patients’ experiences/perspectives
• Unpredictable and insightful findings

Question 14

What are the limitations of qualitative studies?

Answer 14

• difficult to generalise
• sample selection based on certain experiences
• small sample size

Question 15

Which study design would you use to answer the following:

1. How common is oestrogen treatment in women after menopause?
2. What are women’s experiences of taking oestrogen treatment?
3. Is taking oestrogen after menopause associated with a higher risk of breast cancer?
4. Does drug X, hormone treatment , reduce the symptoms of menopause?

Answer 15

1. Cross sectional - to assess prevalence of exposure
2. Qualitative - to explore patient experiences
3. Cohort study - to evaluate association of exposure and disease
4. RTC - to establish the effect of this intervention

Question 16

What are descriptive statistics?

Answer 16

Techniques we use to describe the main features of a data

Question 17

What is statistical inference?

Answer 17

The process of using the value of a sample statistic to make an informed guess about the value of a population parameter

Question 18

What is a variable?

Answer 18

A particular characteristic being studied

Question 19

Explain the 2 main data types?

Answer 19

1. Categorical - can only be assigned to a number of distinct categories e.g sex (male or female)
2. Numerical - takes a numerical value e.g age, weight

Question 20

What can categorical data be divided into?

Answer 20

1. Nominal - no natural ordering e.g sex, blood type

2. Ordinal- ordered categories e.g severity or disease stage

Question 21

What can numerical data be divided into?

Answer 21

1. Continuous - no value limitation e.g weight 87.2345kg

2. Discrete - whole values only e.g number of hospital visits

Question 22

What type of data do bar charts and pie charts show?

Answer 22

Categorical

Question 23

What type of data do scattergraphs show?

Answer 23

Relationships within numeric data (using two continuous variables)

Question 24

What type of data do box plots show?

Answer 24

Summary statistics for numeric data

Question 25

What type of data do histograms show?

Answer 25

Numerical data

Question 26

How do you calculate the median?

Answer 26

1. Sort observations in numerical order 2. Find the mid point 3. If two values lie at the mid point, average them

Question 27

What does the standard deviation tell us about the data?

Answer 27

Summarises the average spread of values around the mean | The larger the SD, the more spread out the values

Question 28

Which data values should you report for normally distributed data?

Answer 28

Report mean and SD

Question 29

Which data values should you report for skewed data?

Answer 29

Report median and inter-quartile range

Question 30

What is a parameter?

Answer 30

A particular characteristic of the population that we are interested in e.g the population mean

Question 31

What are the two common forms of statistical inference?

Answer 31

1. Estimation - the process of using summary statistics from collected sample data to represent the population 2. Hypothesis testing - making a hypothesis about a population and then collect sample data toes whether it gives evidence against the hypothesis

Question 32

What are the 5 steps for calculating standard deviation?

Answer 32

1. Calculate the mean 2. Subtract the mean from every value 3. Square these new values, and add up 4. Divide this total by (n-1) = variance 5. Take the square root = sd

Question 33

What is the standard error?

Answer 33

The standard deviations of different estimates from repeated samples of a population Standard error of the estimate represents the average distance between an estimate and its population parameter

Question 34

What is the frame work for hypothesis testing?

Answer 34

- State the null and alternative hypothesis - Decide a level of significance (p-value cut-off) - Define and evaluate a test statistic - Calculate the p-value - Interpret the results

Question 35

What is the difference between estimation and hypothesis testing?

Answer 35

- estimation is used to generate better understanding of the likely true value of a measurement and the degree of uncertainty surrounding this estimate - hypothesis testing evaluates whether our data provide confidence that our sample estimate is different from another "population" value

Question 36

What are the two types of research?

Answer 36

1. Observational: - cohorts - cross sectional surveys 2. Experimental: - lab experiments - randomised clinical trials

Question 37

What is correlation?

Answer 37

Correlation measures the strength of the linear relationship between two numerical variables

Question 38

When do we use spearman correlation coefficient?

Answer 38

When data is not normally distributed

Question 39

When do we use Pearson correlation coefficient?

Answer 39

to measure the association between two normally-distributed variables

Question 40

What is proportion difference?

Answer 40

Measures the strength of the relationship between two categorical variables

Question 41

When is chi squared used?

Answer 41

- To work out association between two categorical variables (in two independent groups) - difference between two proportions

Question 42

Why is the chi squared test sometimes not accurate?

Answer 42

1. Continuity correction (Yates’s correction) For small sample sizes the chi-squared test is too likely to reject the null hypothesis. A continuity correction can be made to allow for this. 2. Fisher’s exact test If a contingency table fails to meet the conditions required for the chi-squared test then Fisher’s exact test can be used. 

Question 43

What test do we use if theres one continuous variable and one binary variable?

Answer 43

T test

Question 44

Explain the structure of a research paper?

Answer 44

1. Title - clearly describes content 2. Abstract - brief summary of the paper 3. Introduction - explains the problem 4. Methods- describes what was done 5. Results - describes the results obtained 6. Discussion - interpretation and implications 7. References