Transcript Young Statisticians Session - Kate Hargreaves

A brief introduction to explaining
statistics to non-statisticians
Kate Hargreaves
Sr Associate Biostatistics
13th May, 2014
PSI Conference – Young Statistician’s Session
Topics covered
• The perfect trial and sampling
- Practical
• Survival Analysis (Kaplan Meier plots)
• Bias
-
Treatment assignment
Randomisation
Subject selection bias
Assessment bias
• My personal experience
Provided xxxxxxx, 20xx as part of an oral presentation and is qualified by such,
contains forward-looking statements, actual results may vary materially;
Amgen disclaims any duty to update.
2
The perfect trial…
• Test all patients in the population
• Measure all the patients in the population
• Find out the true effect of our treatment
In most cases this cannot be done…
….so we take sample instead
Provided xxxxxxx, 20xx as part of an oral presentation and is qualified by such,
contains forward-looking statements, actual results may vary materially;
Amgen disclaims any duty to update.
3
Provided xxxxxxx, 20xx as part of an oral presentation and is qualified by such,
contains forward-looking statements, actual results may vary materially;
Amgen disclaims any duty to update.
4
Practical - Sampling
• Open your packet of Smarties™
Your Results
• Count the total number of Smarties™
=
• Count the number of ‘Blue’ ones
=
• Calculate the percentage of ‘Blue’ ones
=
Provided xxxxxxx, 20xx as part of an oral presentation and is qualified by such,
contains forward-looking statements, actual results may vary materially;
Amgen disclaims any duty to update.
5
%
Survival Analysis
Patient
1
Death
2
Censored
3
4
5
6
7
8
9
0
3
6
9
Time (Months)
Provided xxxxxxx, 20xx as part of an oral presentation and is qualified by such,
contains forward-looking statements, actual results may vary materially;
Amgen disclaims any duty to update.
6
12
Survival Analysis
Patient
1
Death
2
Censored
3
4
5
6
7
8
9
0
3
6
9
Time from Randomization (Months)
Provided xxxxxxx, 20xx as part of an oral presentation and is qualified by such,
contains forward-looking statements, actual results may vary materially;
Amgen disclaims any duty to update.
7
12
Survival Analysis
Patient
6
Death
9
Censored
3
4
1
2
7
8
5
0
3
6
9
Time from Randomization (Months)
Provided xxxxxxx, 20xx as part of an oral presentation and is qualified by such,
contains forward-looking statements, actual results may vary materially;
Amgen disclaims any duty to update.
8
12
Survival Analysis - Kaplan Meier Curve
Provided xxxxxxx, 20xx as part of an oral presentation and is qualified by such,
contains forward-looking statements, actual results may vary materially;
Amgen disclaims any duty to update.
9
Kaplan Meier Curve
1
0 .9
P ro p o rtio n E v e n t-F re e
0 .8
N e w T re a tm e n t
C o n tro l G ro u p
0 .7
0 .6
0 .5
0 .4
0 .3
0 .2
0 .1
0
0
6
12
18
24
T im e fro m R a n d o m iz a tio n (M o n th s )
Provided xxxxxxx, 20xx as part of an oral presentation and is qualified by such,
contains forward-looking statements, actual results may vary materially;
Amgen disclaims any duty to update.
10
30
36
Types of bias
Subject selection bias
V
Randomisation
Provided xxxxxxx, 20xx as part of an oral presentation and is qualified by such,
contains forward-looking statements, actual results may vary materially;
Amgen disclaims any duty to update.
Treatment assignment bias
11
My Experience
• Workshops are key for keeping people interested
• Bare in mind the set up of the room
• If teaching a full day course, try and share the work
• Talk about real studies
• Analysis of papers (and the statistics in them)
• Apologise for the jargon or any repeats
• Amount of formulae
It is very difficult for a large group to pitch statistical
training at the correct level
Provided xxxxxxx, 20xx as part of an oral presentation and is qualified by such,
contains forward-looking statements, actual results may vary materially;
Amgen disclaims any duty to update.
12
Any questions?
Kate Hargreaves
Sr Associate Biostatistics
13th May, 2014
PSI Conference, Young Statistician’s Session
Acknowledgements – James Matcham