February 13, 2017

Outline

  • Current state of clinical research

  • What the scientific community can do to improve clinical research

  • What you can do to improve your own research

Objectives

  • Provide an overview of complex problems and solutions to clinical research

  • Focus on methodological and statistical issues

Why do you want to do research?

"Why most published research findings are false" (Ioannidis, 2005)

  • False findings may be "the majority of published research claims"

  • Due to statistical likelihood of finding a positive (or false positive) result

  • Bias in studies

  • Testing by several independent teams

Bias and testing by several independent teams

Why so much variability?

  • Different:
    • Statistics
    • Methods
    • Measures
    • Populations
    • Locations
    • Times

  • It is difficult to account for heterogeneity

  • Bias is usually unintentional

Bias in studies: P-values (Wasserstein & Lazar, 2016)

  1. P-values can indicate how incompatible the data are with a specified statistical model.
  2. P-values do not measure the probability that the studied hypothesis is true, or the probability that the data were produced by random chance alone.
  3. Scientific conclusions and business or policy decisions should not be based only on whether a p-value passes a specific threshold.
  4. Proper inference requires full reporting and transparency.
  5. A p-value, or statistical significance, does not measure the size of an effect or the importance of a result.
  6. By itself, a p-value does not provide a good measure of evidence regarding a model or hypothesis.

P hacking

Example

See Greenland et al., (2016) for mor information about interpreting and using pvalues, confidence intervals and power.

Why most clinical research is not useful (Ioannidis, 2016)

  • 85% of research investments are wasted (Macleod et al., 2014)

  • Bias in studies leads to impediments in meta-research

  • Researchers are not incentivized appropriately

Research Incentives Example

  • Novel publications and grants over replication studies

  • Positive over null findings (journals)

  • Quantity over quality

Things to consider (Ioannidis, 2016)

  • Problem base: Is there a health problem that is big/important enough to fix?

  • Context placement: Has prior evidence been systematically assessed to inform (the need for) new studies?

  • Information gain: Is the proposed study large and long enough to be sufficiently informative?

  • Pragmatism: Does the research reflect real life? If it deviates, does this matter?

  • Patient centeredness: Does the research reflect top patient priorities?

  • Value for money: Is the research worth the money?

  • Feasibility: Can this research be done?

  • Transparency: Are methods, data, and analyses verifiable and unbiased?

How can WE improve clinical research

"How to make more published research true" (Ioannidis, 2014)

  • Large-scale studies

  • Reproducibility practices (Begley & Ioannidis, 2015)

  • More appropriate analyses

  • Improved study design standards

  • Change incentives for researchers

  • Preregister studies/results

Issues with methods

  • Measurement
    • Reliability vs validity
    • Use objective measures when possible
    • Use validated self-report measures

  • RCTs vs Observational studies (Van Poucke, Thomeer, Heath, & Vukicevic, 2016)
    • What is your research question
    • What data can you ethically and practically collect

  • Advanced Methods The Methodology Center
    • Multiphase Optimization Strategy (MOST)
    • Sequential Multiple Assignment Randomized Trials (SMART)
    • Just In Time Adaptive Interventions (JITAI)

Issues with statistics

  • Utility in p-values
    • Focus more on precision of effect sizes
    • Consider Bayesian Credible Intervals

  • Missing data
    • Missing data mechanisms
    • Avoid missing data!

  • Meta-analysis
    • Garbage in garbage out
    • Fairly simple to conduct
    • A good way to learn about a subject area and gaps

Theory

  • Use theories when possible

  • Adapt theories based on evidence

  • Recognize the limitations of a theory (Prestwich et al., 2014)

Reproducibility

  • “The idea that data analyses, and more generally, scientific claims, are published with their data and software code so that others may verify the findings and build upon them” (from Coursera)

  • http://ropensci.github.io/reproducibility-guide/

  • Clearly delineate how data are managed, manipulated, and analyzed in order to allow others to replicate findings with no (or minimal) assistance

  • Why this is hard to achieve
    • Tight deadlines
    • Focus on quantity over quality (on both ends)
    • Not how most of us were trained
    • Heavy up front costs (e.g., time)

How can YOU improve clinical research

Research practices for everyday use

  • Stay up to date on the literature
    • Feedly
    • Google Alerts

  • Be comfortable with not having a comprehensive understanding of complex topics

  • Learn to work with data analysts/biostatisticians

  • Get feedback

  • Collaborate with people who know more than you and are good teachers

Research practices for everyday use (cont.)

  • Participate in transdisciplinary research

  • Familiarize yourself with research outside of your discipline

  • Follow researchers who do good research and emulate them
    • John Ioannidis
    • Andrew Gelman

  • Get really good at writing (Zinsser) and write a lot (Silva)

Epistemology: How do you learn best?

  • Methods and statistics change just as substantive areas do

  • How do you learn best
    • Didactics
    • Books
    • Practice
    • Online training (DataCamp, Coursera, Udemy)

My humble opinion

  • Research training should focus on:
    • Philosophy
    • English/writing
    • Methods
    • Statistics

  • Focus on learning how to ask and answer questions

  • Substantive information is easier to learn

Why are you telling me this?

  • Doing good science is really hard

  • We can do better
    • Structural changes (granting agencies, journals, academic institutions)
    • More personal responsibility

  • Chase ideas instead of grant dollars
    • Focus on programmatic and collaborative research

References

Begley, C. G., & Ioannidis, J. P. (2015). Reproducibility in science improving the standard for basic and preclinical research. Circulation Research, 116(1), 116–126. https://doi.org/10.1161/circresaha.114.303819

Greenland, S., Senn, S. J., Rothman, K. J., Carlin, J. B., Poole, C., Goodman, S. N., & Altman, D. G. (2016). Statistical tests, p values, confidence intervals, and power: A guide to misinterpretations. European Journal of Epidemiology, 31(4), 337–350. https://doi.org/10.1007/s10654-016-0149-3

Ioannidis, J. P. (2005). Why most published research findings are false. PLoS Med, 2(8), e124. https://doi.org/10.1371/journal.pmed.0020124

Ioannidis, J. P. (2014). How to make more published research true. PLoS Med, 11(10), e1001747. https://doi.org/10.1371/journal.pmed.1001747

Ioannidis, J. P. (2016). Why most clinical research is not useful. PLOS Medicine, 13(6), e1002049. https://doi.org/10.1371/journal.pmed.1002049

Macleod, M. R., Michie, S., Roberts, I., Dirnagl, U., Chalmers, I., Ioannidis, J. P., … Glasziou, P. (2014). Biomedical research: Increasing value, reducing waste. The Lancet, 383(9912), 101–104. https://doi.org/10.1016/s0140-6736(13)62329-6

Prestwich, A., Sniehotta, F. F., Whittington, C., Dombrowski, S. U., Rogers, L., & Michie, S. (2014). Does theory influence the effectiveness of health behavior interventions? Meta-analysis. Health Psychology, 33(5), 465–474. https://doi.org/10.1037/a0032853

Van Poucke, S., Thomeer, M., Heath, J., & Vukicevic, M. (2016). Are randomized controlled trials the (g) old standard? From clinical intelligence to prescriptive analytics. Journal of Medical Internet Research, 18(7), e185. https://doi.org/10.2196/jmir.5549

Wasserstein, R. L., & Lazar, N. A. (2016). The ASA’s statement on p-values: Context, process, and purpose. The American Statistician, 70(2), 129–133. https://doi.org/10.1080/00031305.2016.1154108