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Careers in Statistics. The Role of a Biostatistician Presentation at Central College Pella, Iowa. What comes to mind when you hear the word “statistics”?. Sports statistics? Vital health statistics? Just numbers?. Leading causes of death in the U.S.

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careers in statistics

Careers in Statistics

The Role of a Biostatistician

Presentation at Central College

Pella, Iowa

what comes to mind when you hear the word statistics
What comes to mind when you hear the word “statistics”?
  • Sports statistics?
  • Vital health statistics?
  • Just numbers?
cancer death rates for men us 1930 2000
Cancer Death Rates*, for Men, US, 1930-2000

Rate Per 100,000




Colon & rectum




cancer death rates for women us 1930 2000
Cancer Death Rates*, for Women, US, 1930-2000




Colon & rectum




tobacco use in the us 1900 2000
Tobacco Use in the US, 1900-2000

Per capita cigarette consumption

Male lung cancer death rate

Female lung cancer death rate

trends in overweight prevalence adults 18 and older us 1992 2002
Less than 50%

50 to 55%

More than 55%

State did not participate in survey

Trends in Overweight* Prevalence (%), Adults 18 and Older, US, 1992-2002





*Body mass index of 25.0 kg/m2or greater

Source: Behavioral Risk Factor Surveillance System, CD-ROM (1984-1995, 1998) and Public Use Data Tape (2002), National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, 1997, 2000, 2003.

discipline of statistics
Discipline of Statistics
  • The statistics presented here involve massive efforts to collect the data, followed by simple calculations.
  • We see differences, but are they meaningful? Could they have happened by chance?
  • If we see trends that we do not like, what can we do to effect change?
discipline of statistics1
Discipline of Statistics
  • Numbers carry information, but we need numerical reasoning to make their meaning clear.
  • The discipline of statistics uses mathematical tools to quantify uncertainty and assign a likelihood that what we see could have happened by chance.
  • Biostatistics is just statistics applied in the health sciences.
  • Mathematics and math logic play critical roles.
typical research questions
Typical Research Questions
  • We rely heavily on medications to treat diseases and medical conditions.
    • How do we know that they work (are efficacious) and are safe?
  • Heart disease is the #1 cause of death.
    • How can we assess if an intervention is effective in reducing a person’s risk?
competing possible errors
Competing Possible Errors
  • Any research study has the possibility of making one of two types of errors:
    • Type I: Declaring a significant effect when in fact there is none.
    • Type II: Failing to find a significant difference when there is one.
  • In statistics, we use mathematical theory and modeling to find optimal decision rules and choose sample sizes which will reduce the likelihood of these errors to acceptable levels.
example clinical trials
Example: Clinical Trials
  • One type of research design to address such questions is known as a clinical trial.
  • In a clinical trial, patients are randomly assigned to either the new drug/treatment or “standard care”.
  • When possible, both patients and doctors are blinded to the assignment.
clinical trials
Clinical Trials

IHAST2 Trial


Hypothermia for

Aneurysm Surgery Trial

Michael Todd MD, Bradley Hindman MD,

William Clarke PhD, James Torner PhD

University of Iowa

and the IHAST2 Investigators.

Supported by NIH RO1 NS38554

  • Hypothermia was first used in neurosurgery in 1955.
  • Based on research experience with animals, it was believed that cooling the body before neurosurgery would be protective against central nervous system (CNS) insults.
  • At present, at least 50% of current open neurovascular cases are cooled (Pemberton, 2003).
  • However, this was being done without a rigorous assessment of outcomes.
  • In 1999, U. of Iowa researchers published the results of a small pilot clinical trial on this*.
  • They randomly assigned 114 patients with and without acute aneurysmal subarachnoid hemorrhage (SAH) to either cooling or normal body temperature before surgery
    • Cooling = target body temperature of 33.5 C
    • Normal = body temperature 37C

Hindman, Todd, et al. Neurosurgery. 1999 Jan;44(1):23-32; discussion 32-3.


Outcome = Glasgow Outcome Score at Three Months

  • Is it beyond reasonable doubt that hypothermia is working?
  • SAH patients (n=52) : 71% vs. 57% =“good”
    • Looks like hypothermia is helping.
  • No SAH (n=62): 77% vs. 76% = “good”
    • Looks like little effect of hypothermia.
  • Answer:

No - there is reasonable doubt.

  • Statistical methods were used to determine

(1) These differences, given this sample size, could have reasonably occurred by chance .

(2) It would need a randomized clinical trial of at least 900 patients to assure that we could detect a 10% improvement (from 65% to 75%) in the Glasgow outcome score at three months with 90% power.

  • The follow-up International, multi-center randomized clinical trial was funded by NIH (IHAST2).
  • 1000 SAH patients undergoing craniotomies for aneurysm clipping were randomized to either hypothermia or normal body temperature.
  • Primary outcome measure: Glasgow Outcome Score (GOS) at 3 months
ihast2 glasgow outcome score
IHAST2: Glasgow outcome score

The previous 71%-57% difference has now shrunk to a 66%-63% difference


Now, is it beyond reasonable doubt that hypothermia is working?

  • This study had a large enough sample size to find a meaningful difference in “good” outcomes due to hypothermia (should it work) with high probability.*

Beyond reasonable doubt, it simply does not work as believed.

* Many other outcomes were also tested. All consistently showed no benefit.

missouri turkey hunting survey
Missouri Turkey Hunting Survey
  • The Missouri Department of Conservation is interested in turkey hunting success rates.
  • Can we obtain an estimate of the hunting success rate in every county on every day of the hunting season even if we don’t have a sample from that county?

(small area estimation)

what do statisticians do
What do statisticians do?
  • Surveys
    • political surveys
    • National Health and Nutrition Examination Survey
  • Government Operations
    • Census Bureau
    • FDA
  • Scientific Research
    • Cancer trends
    • Survival probability
    • Genetics
  • Business and Industry
    • Pharmaceuticals



Economics, Engineering,


Computer Science




Chemistry, Physics

Areas where


are used

Health &


Genetics, Clinical Trials,





Ecology, Forestry,

Animal Populations


Census, Law,

National Defense


roles of a biostatistician
Roles of a Biostatistician
  • Guardian of the science.
    • Help write the proposal to get this study funded.
    • Maintain an unbiased perspective.
    • Determine which data needed to be collected.
    • Determine what methods would be used.
    • Anticipate how proposed changes in the program would affect ability to make inferences and argue against them when needed.
    • Develop new methods when needed.
roles of a biostatistician1
Roles of a Biostatistician
  • Keeper of the Data.
      • Work with different state and federal agencies to obtain data.
      • Check data for recognizable errors.
      • Merge data from different sources.
      • Maintain and secure the project database.
      • Work with others (e.g., national evaluators, statistical coordinating centers) to blend your data with other data.
roles of a biostatistician2
Roles of a Biostatistician
  • Analytic Support
      • Investigate the data from many angles.
      • Assess assumptions of proposed models.
      • Fit statistical models.
      • Interpret results of the models for the research team.
      • Make sure that the investigators do not draw conclusions beyond what can be supported by the data.
  • Author (Write up results / provide graphics.)
what about salaries
What About Salaries?
  • Annual (median) salary with 0-1.9 years of experience for

Masters PhD

- Statistician 60,000 83,000

- Male Statistician 56,500 83,000

- Female Statistician 62,000 83,000

- Assistant Professor (4 year college) 53,000

- Assistant Professor (Research) 63,000

- Pharmaceutical statistician 73,000 83,000


life as a graduate student
Life as a Graduate Student
  • What do you do as a graduate student?
    • Classwork
    • Teaching assistants
    • Research assistants
    • Go to football games!
variety of scientific projects
Variety of scientific projects

As you can tell, people work on various different projects. The following are brief excerpts from some recent projects.

driving simulator nads
Driving Simulator (NADS)

A shared-use research facility operated by The University of Iowa, The NADS was created to conduct research which will help save lives, reduce the costs of vehicle crashes, and lead to better and safer vehicles, roadways, and drivers.

iowa cochlear implant center
Iowa Cochlear Implant Center

While normal hearing has increased significantly, implants still do not reproduce a high quality of music.

Is it beneficial to have two cochlear implants for those who are profoundly deaf?

iowa bridge to employment study
Iowa Bridge to Employment Study

Mental Illness Group

Mental Retardation Group

  • Purpose: To determine if special services provided to Iowans with disabilities would increase the likelihood of employment.
Total Physicians

Cancer Crude Rates



< 10,000


10,000 - 20,000

> 20,000

Rate Per 100,000 Population



State of Iowa








holden comprehensive cancer center
Holden Comprehensive Cancer Center

Tumor growth curve estimates from a mixed linear models analysis.

Group comparisons indicate differences between specific groups at the 5% level of significance.

Spatial statistics

Radon concentrations measured in the basements of homes in Iowa.

thank you
Thank you!

Jake Oleson

Central College

class of 1997