With summer over, we are re-starting the statistics and epidemiology methods seminar series. Please find a schedule below for the next few months.
The sessions are a chance to discuss methodology in epidemiological research, and are intended as a platform for learning and discussion. Everyone is welcome, and we would welcome any suggestions for future sessions. I would also be happy to hear from you if you are conducting research using a new or under-utilized approach and would like to lead an upcoming meeting.
Summaries for all sessions will be up on this website.
Sue Mallet, What makes a prognostic model more reliable for use in clinical practice?
22 September 2010
1-2pm
Rosemary Rue Building, Teaching room A
Paper discussion, paper to be decided
20 October 2010
1-2pm
Rosemary Rue Building, Teaching room A
Richard Peto, Rubbishing random effects
17 November 2010
12:30-1:30pm
CTSU Main Meeting Room 1st floor Richard Doll Building
Ly-mee Yu, How to handle missing data in trials
15 December
1-2pm
Rosemary Rue Building, Teaching room A
Monday, 6 September 2010
Thursday, 10 June 2010
Update on seminar series
If you are here looking for the next scheduled seminar, sorry for being so quiet!
We have teamed up with the Clinical Trial Service Unit (CTSU) and aim to bring a new schedule of statistical primers, seminars and paper discussions starting from September 2010. I will circulate more details in September.
In the meantime, if you have an idea for a seminar or would like to present some of your own work, please do email me and let me know!
Nada
We have teamed up with the Clinical Trial Service Unit (CTSU) and aim to bring a new schedule of statistical primers, seminars and paper discussions starting from September 2010. I will circulate more details in September.
In the meantime, if you have an idea for a seminar or would like to present some of your own work, please do email me and let me know!
Nada
Tuesday, 27 April 2010
The power of graphs in meta analysis
We met today (April 26) to discuss the paper 'More than numbers: The power of graphs in meta-analysis' by Leon Bax and colleagues.
We went through the different plots types (short powerpoint presentation below). A few of the points I picked up on included:
- Limitations of the funnel plot, including the need for at least 25 studies or more to determine whether any studies are 'missing'.
- The need for accurate and complete trial registers to estimate publication bias
- Reporting the funnel plot statistic instead of including the plot in a paper
- The usefulness of L'Abbe plot, which can be extended to other studies with continuous variables. It was also pointed out that L'Abbe plot demonstrates whether the different studies report a constant risk reduction/increase which may be useful. There is a 'bubble plot' in Excel which can be used to draw a L'Abbe plot.
Many of the attendees said that they generally didn't report any plots other than a forest plot in a meta-analysis. Paul G. said that he sometimes tries a L'Abbe plot, and has also used 'Rosenthal's file drawer N' method to estimate publication bias by estimating how many studies of no effect would be needed to change the summary estimate.
We had some concerns about the simulation studies in this paper. The researchers who scored the graphs' ability to demonstrate hetereogeneity or bias may have benefitted from a training period, and may have preferred the forest plot due to familiarity. We thought that it may have been better to have more raters scoring fewer graphs, and agreed that most of the different plots were poor at assessing publication bias (Table 4).
Our next meeting is scheduled for May 19.
Meta Analysis Plots
We went through the different plots types (short powerpoint presentation below). A few of the points I picked up on included:
- Limitations of the funnel plot, including the need for at least 25 studies or more to determine whether any studies are 'missing'.
- The need for accurate and complete trial registers to estimate publication bias
- Reporting the funnel plot statistic instead of including the plot in a paper
- The usefulness of L'Abbe plot, which can be extended to other studies with continuous variables. It was also pointed out that L'Abbe plot demonstrates whether the different studies report a constant risk reduction/increase which may be useful. There is a 'bubble plot' in Excel which can be used to draw a L'Abbe plot.
Many of the attendees said that they generally didn't report any plots other than a forest plot in a meta-analysis. Paul G. said that he sometimes tries a L'Abbe plot, and has also used 'Rosenthal's file drawer N' method to estimate publication bias by estimating how many studies of no effect would be needed to change the summary estimate.
We had some concerns about the simulation studies in this paper. The researchers who scored the graphs' ability to demonstrate hetereogeneity or bias may have benefitted from a training period, and may have preferred the forest plot due to familiarity. We thought that it may have been better to have more raters scoring fewer graphs, and agreed that most of the different plots were poor at assessing publication bias (Table 4).
Our next meeting is scheduled for May 19.
Meta Analysis Plots
Friday, 16 April 2010
April 21 meeting options
Dear all,
I hope that some of you will be able to join us next week for the
stats and epidemiology journal club on Wednesday April 21. The
meeting will be held at 1pm in the 2nd floor meeting room in the
Rosemary Rue Building.
I have attached three possible papers for discussion. If you are
interested in coming, please send me back your vote for which paper
you'd like to discuss. The options are:
1. Bias in identifying and recruiting participants in cluster
randomised trials: what can be done? Sandra Eldridge and colleagues,
BMJ. 2009 Oct 9;339:b4006.
A discussion of how to design cluster randomized trials to minimize
selection bias
2. More Than Numbers: The Power of Graphs in Meta-Analysis. Leon Bax
and colleagues, Am J Epidemiol. 2009 Jan 15;169(2):249-55
What graphs should we use to report the results from a meta analysis?
A comparison for some of the popular options and limitations in each.
3. Power for studies with random group sizes. Walter T. Ambrosius,
Stat Med. 2010 Mar 11.
How to appropriately conduct a power calculation for observational studies
Let me know by next Monday and I will circulate the winning paper! Just email me at nada.khan@dphpc.ox.ac.uk.
I hope that some of you will be able to join us next week for the
stats and epidemiology journal club on Wednesday April 21. The
meeting will be held at 1pm in the 2nd floor meeting room in the
Rosemary Rue Building.
I have attached three possible papers for discussion. If you are
interested in coming, please send me back your vote for which paper
you'd like to discuss. The options are:
1. Bias in identifying and recruiting participants in cluster
randomised trials: what can be done? Sandra Eldridge and colleagues,
BMJ. 2009 Oct 9;339:b4006.
A discussion of how to design cluster randomized trials to minimize
selection bias
2. More Than Numbers: The Power of Graphs in Meta-Analysis. Leon Bax
and colleagues, Am J Epidemiol. 2009 Jan 15;169(2):249-55
What graphs should we use to report the results from a meta analysis?
A comparison for some of the popular options and limitations in each.
3. Power for studies with random group sizes. Walter T. Ambrosius,
Stat Med. 2010 Mar 11.
How to appropriately conduct a power calculation for observational studies
Let me know by next Monday and I will circulate the winning paper! Just email me at nada.khan@dphpc.ox.ac.uk.
Friday, 19 March 2010
Meeting on 17 March 2010 - Capture/Recapture
Thanks to Geraldine Surman and Matthias Pierce from NPEU for a great talk on capture/recapture methods and applications in their own projects. I've uploaded their talk rfom Wednesday, which includes some Stata code and may be of interest to other people who wish to apply this method in their own research. Both Geraldine and Matthias are happy for people to contact them to discuss capture/recapture in further detail. Next meeting is scheduled for 21 April.
Capture Recapture Mar 10
Capture Recapture Mar 10
Thursday, 21 January 2010
Meeting on 20 January - Missing data and Mendelian randomization
Dear all,
Hope you enjoyed Nicola Fitz- Simon's discussion on missing data and Mendelian randomization. I've uploaded her slides (see below) so do take a look if you missed the meeting. Our next meeting is scheduled for Wednesday February 17.
Missing Data and Mendelian Random is at Ion
Hope you enjoyed Nicola Fitz- Simon's discussion on missing data and Mendelian randomization. I've uploaded her slides (see below) so do take a look if you missed the meeting. Our next meeting is scheduled for Wednesday February 17.
Missing Data and Mendelian Random is at Ion
Wednesday, 16 December 2009
December 16 discussion - Am J Epi paper by Kurth et al
Today we discussed the paper by Kurth et al in the Am J Epi . Some slides on our discussion can be found just below this post. Our next meeting is on Wednesday, January 20. Nicola Fitz Simons will be leading a discussion on missing data and Mendelian randomization. Happy Christmas!
December Meeting
December Meeting
Monday, 14 December 2009
Next meeting - 16 December, 1pm
Our next meeting is on 16 December 2009 (Wednesday) at 1pm in the 2nd floor meeting room. The paper up for discussion is:
Kurth et al
American Journal of Epidemiology, 2006; 163: 262-270
Results of Multivariable Logistic Regression, Propensity Matching, Propensity Adjustment and Propensity-based Weighting under Conditions of Nonuniform Effect
I've put together a few slides to get our discussion going - I thought that some points for discussion could include the benefits and disadvantages of different adjustment methods, and a consideration of what question we're asking of the data when we conduct analysis.
Hope to see you there! I'll bring some Christmas treats for us to snack on during the meeting. Let me know if you can't get a hold of the paper full text.
Kurth et al
American Journal of Epidemiology, 2006; 163: 262-270
Results of Multivariable Logistic Regression, Propensity Matching, Propensity Adjustment and Propensity-based Weighting under Conditions of Nonuniform Effect
I've put together a few slides to get our discussion going - I thought that some points for discussion could include the benefits and disadvantages of different adjustment methods, and a consideration of what question we're asking of the data when we conduct analysis.
Hope to see you there! I'll bring some Christmas treats for us to snack on during the meeting. Let me know if you can't get a hold of the paper full text.
Thursday, 29 October 2009
Summary of our second meeting on Oct 26
Many thanks to Karen Smith for her clear and informative seminar on the use and application of interrupted time series analysis. Karen has kindly allowed me to publish her Powerpoint slides online, so if you are interested in seeing her talk, it's just below this post. Our next meeting is on Wednesday, November 18 at 1pm. Nicola Fitz-Simons, who is based at NPEU, will be leading a seminar based on some of her methodological research.
Interrupted Time Series
Interrupted Time Series
Monday, 12 October 2009
Seminar by Karen Smith
The next journal club will be led by Karen Smith, senior medican statistician at the Centre for Statistics in Medicine here in Oxford. Karen will be leading a discussion on interrupted time series analysis based on a paper she worked on, which was recently published in the BMJ. The paper can be found here:
Effect of withdrawal of co-proxamol on prescribing and deaths from drug poisoning in England and Wales: time series analysis
Please do join us for this talk and discussion - just to note that Karen will be giving her talk on Monday, October 26, NOT October 21 as we had previously scheduled. All seminars will take place from 1-2pm, 2nd floor meeting room, Rosemary Rue building.
Effect of withdrawal of co-proxamol on prescribing and deaths from drug poisoning in England and Wales: time series analysis
Please do join us for this talk and discussion - just to note that Karen will be giving her talk on Monday, October 26, NOT October 21 as we had previously scheduled. All seminars will take place from 1-2pm, 2nd floor meeting room, Rosemary Rue building.
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