1. Bob Marshall, MD MPH MISM DoD Clinical Informatics Fellowship
Predictive Analytics
Bob Marshall, MD MPH MISM
DoD Clinical Informatics Fellowship

2. Definition
Branch of data mining concerned with prediction of future probabilities/outcomes and trends
Central element of predictive analytics is the predictor, variable that can be measured for individual or other entity to predict future behavior
Multiple predictors combined into predictive model, which, when subjected to analysis, can be used to forecast future probabilities with an acceptable level of reliability

3. Definition cont
In predictive modeling, data is collected, statistical model formulated, predictions are made and the model is validated (or revised) as additional data becomes available
Model may employ simple linear equation or complex neural network, mapped out by sophisticated software
Models capture relationships among many factors to allow assessment of risk or potential (i.e., future) associated with particular set of conditions

4. End Effect
Defining functional effect of these technical approaches is that predictive analytics provides a predictive score (probability) for each individual in order to determine, inform, or influence organizational processes that pertain across large numbers of individuals
Core of predictive analytics relies on capturing relationships between explanatory variables and predicted variables from past occurrences, and exploiting them to predict the unknown outcome

5. Dependencies
Accuracy and usability of results depend greatly on the level of data analysis and the quality of assumptions
Also very dependent on the accuracy or integrity of the different variable/factor data
Inaccurate variable/factor date = inaccurate predictions

6. Predictive Analytics and Big Data
Predictive analytics is enabler of big data
Predictive analytics enable organizations to use big data (both stored and real time) to move from an historical view to a forward-looking perspective of the customer/ patient

7. Predictive Models
models of the relation between the specific performance of a unit in a sample and one or more known attributes or features of the unit.
The objective of the model is to assess the likelihood that a similar unit in a different sample will exhibit the specific performance.
Predictive models often perform calculations during live transactions, for example, to evaluate the risk or opportunity of a given customer or transaction, in order to guide a decision

8. Predictive Models
Available sample units with known attributes and known performances are referred to as the “training sample.”
Units in other samples, with known attributes but unknown performances, are referred to as “out of [training] sample” units.
Out of sample units bear no chronological relation to training sample units
The out of sample unit may be from the same time as the training units, from a previous time, or from a future time

9. Examples
Example 1: training sample may consists of literary attributes of writings by Victorian authors, with known attribution, and the out of sample unit may be newly found writing with unknown authorship; a predictive model may aid in attributing a work to a known author.
Example 2: analysis of blood splatter in simulated crime scenes in which the out of sample unit is the actual blood splatter pattern from a crime scene

10. Descriptive Models
Descriptive models quantify relationships in data in a way that is often used to classify customers or prospects into groups.
Unlike predictive models that focus on predicting a single customer behavior (such as credit risk), descriptive models identify many different relationships between customers or products.
Descriptive models can be used, for example, to categorize customers by their product preferences and life stage.
Descriptive modeling tools can be utilized to develop further models that can simulate large number of individualized agents and make predictions

11. Decision Models
Decision models describe relationship between all elements of a decision —known data (including results of predictive models), decision, and forecast results of the decision — in order to predict results of decisions involving many variables
Decision models generally used to develop decision logic or set of business rules that will produce desired action for every customer (patient) or circumstance

12. Clinical Decision Support
Predictive analysis in health care primarily used to determine which patients at risk of developing certain conditions, like diabetes, asthma, heart disease, and other lifetime illnesses
Additionally, sophisticated clinical decision support systems incorporate predictive analytics to support medical decision making at the point of care
Working definition proposed by Robert Hayward of the Centre for Health Evidence: “Clinical Decision Support Systems link health observations with health knowledge to influence health choices by clinicians for improved health care.”

13. Population Health
Can use predictive analytics to forecast disease burden and healthcare resource utilization rates for a given population
Can use zip code analysis for median income, age distribution, gender prevalence, education level, crime statistics, and more readily available historical/demographic factors
Combine these with national statistics on disease burden, accidents/trauma and healthcare utilization rates to predict future use/needs

14. Analytic Techniques
The approaches and techniques used to conduct predictive analytics can broadly be grouped into regression techniques and machine learning techniques
Regression models are mainstay of predictive analytics.
Focus lies on establishing mathematical equation as model to represent interactions between the different variables in consideration.
Machine learning originally employed to develop techniques to enable computers to learn
For very complex underlying relationships with unknown dependencies, machine learning techniques can emulate human cognition and learn from training examples to predict future events

15. Linear Regression Model
Analyzes relationship between response or dependent variable and set of independent or predictor variables
Relationship expressed as an equation that predicts response variable as linear function of the parameters
Parameters adjusted so that a measure of fit is optimized
Much of the effort in model fitting focused on minimizing size of residual, as well as ensuring that it is randomly distributed with respect to model predictions
Generally used when response variable is continuous and has an unbounded range

16. Discrete Choice Models
Response variable may not be continuous but rather discrete
While mathematically feasible to apply multivariate regression to discrete ordered dependent variables, some of the assumptions behind the theory of multivariate linear regression no longer hold
Are other techniques, such as discrete choice models, better suited for this type of analysis
If dependent variable discrete, some of those superior methods are logistic regression, multinomial logit and probit models
Logistic regression and probit models used when dependent variable is binary

17. Time Series Models
Time series models used for predicting or forecasting future behavior of variables
These models account for fact that data points taken over time may have internal structure (such as autocorrelation, trend or seasonal variation) that should be accounted for
Modeling dynamic path of a variable can improve forecasts since predictable component of series can be projected into the future
Two commonly used forms of these models are autoregressive models (AR) and moving-average (MA) models

18. Survival/Duration Analysis
Survival analysis is another name for time to event analysis
These techniques were primarily developed in the medical and biological sciences
Important concept in survival analysis is hazard rate, defined as probability that the event will occur at time t conditional on surviving until time t
Another concept related to hazard rate is survival function which can be defined as probability of surviving to time t

19. Machine Learning Techniques
Neural networks
Multilayer perceptron (MLP)
Radial basis functions (RBF)
Support vector machines (SVM)
Naïve Bayes
k – nearest neighbors (KNN)
Geospatial predictive modeling

20. Implementing Predictive Analytics
The first thing you need to get started using predictive  analytics is a problem to solve
Second, you’ll need data
You will need someone with data management experience to help cleanse and prep the data for analysis
You need someone who understands both the data and the problem to be solved to the prepare the data for predictive modeling
How you define your target is essential to how you can interpret the outcome
After that, the predictive model building begins

21. Questions