MEBI 591B Public Health Informatics Colloquium © Phil Hurvitz, 2006 Multi-Sensor Board Analysis Plan Phil Hurvitz University of Washington College of Architecture and Urban Planning Urban Form Lab gis.washington.edu/phurvitz MEBI 591B Public Health Informatics Colloquium

MEBI 591B Public Health Informatics Colloquium © Phil Hurvitz, 2006Slide 2 (of 37) Confidentiality Unpublished Data Do Not Distribute

MEBI 591B Public Health Informatics Colloquium © Phil Hurvitz, 2006Slide 3 (of 37) Overview Introduction/Background/Relevance What is GIS, and what is its role in Public Health? Measuring Physical Activity Measuring the Built Environment ECOR Funded Research: Assessing the reliability and validity of the Multi-Sensor-Board for the direct measurement of physical activity, environmental characteristics, and the built environment Analysis Plan Suggestions/Questions

MEBI 591B Public Health Informatics Colloquium © Phil Hurvitz, 2006Slide 4 (of 37) Overview Introduction/Background What is GIS, and what is its role in Public Health? Measuring Physical Activity Measuring the Built Environment ECOR Funded Research: Assessing the reliability and validity of the Multi-Sensor-Board for the direct measurement of physical activity, environmental characteristics, and the built environment Analysis Plan Suggestions/Questions

MEBI 591B Public Health Informatics Colloquium © Phil Hurvitz, 2006Slide 5 (of 37) Introduction/Background Obesity threatens personal health and may bankrupt the US health care system Obesity incidence has increased dramatically over the last 20 years Source: CDC BRFSS (

MEBI 591B Public Health Informatics Colloquium © Phil Hurvitz, 2006Slide 6 (of 37) Introduction/Background: Obesity trends

MEBI 591B Public Health Informatics Colloquium © Phil Hurvitz, 2006Slide 7 (of 37) Introduction/Background Health care system says, “Eat less, exercise more.”

MEBI 591B Public Health Informatics Colloquium © Phil Hurvitz, 2006Slide 8 (of 37) Introduction/Background Increasing physical activity is important in the fight against obesity The built environment can either promote or hinder physical activity, e.g., Presence/absence of sidewalks Presence/absence of utilitarian destinations (e.g., restaurants, retail stores, restaurants, banks) How does physical activity vary with different compositions and configurations of environment?

MEBI 591B Public Health Informatics Colloquium © Phil Hurvitz, 2006Slide 9 (of 37) Overview Introduction/Background What is GIS, and what is its role in Public Health? Measuring Physical Activity Measuring the Built Environment ECOR Funded Research: Assessing the reliability and validity of the Multi-Sensor-Board for the direct measurement of physical activity, environmental characteristics, and the built environment Analysis Plan Suggestions/Questions

MEBI 591B Public Health Informatics Colloquium © Phil Hurvitz, 2006Slide 10 (of 37) What is GIS? A computer-based method for Capture, Storage, Manipulation, Analysis, and Display of spatially referenced data

MEBI 591B Public Health Informatics Colloquium © Phil Hurvitz, 2006Slide 11 (of 37) What is GIS? Any object or phenomenon that is or can be placed on a map can be stored, managed, and analyzed in a GIS. Built environment features (streets, buildings, bus routes, restaurants, schools) Households (address points, tax-lot polygons) Individuals (points or travel lines/polygons) Ground surface elevation or slope Movement of objects through time and/or space Demographics, socioeconomics Patient residence, work, and school locations Disease occurrence

MEBI 591B Public Health Informatics Colloquium © Phil Hurvitz, 2006Slide 12 (of 37) GIS combines coordinate (map) and attribute (tabular/statistical) data

MEBI 591B Public Health Informatics Colloquium © Phil Hurvitz, 2006Slide 13 (of 37) How GIS deals with spatial layers

MEBI 591B Public Health Informatics Colloquium © Phil Hurvitz, 2006Slide 14 (of 37) Introduction to GIS Analytical techniques (a very simple list) Spatial aggregation Disease rates per census or zip code area Buffering How many fast food restaurants within 1 mile of schools? Overlay analysis How much of each census block group is affected by a toxic aerosol plume? How many of each type of land use is within ½ mile of all locations visited within a day? Surface generation, interpolation Trend surfaces Kriging

MEBI 591B Public Health Informatics Colloquium © Phil Hurvitz, 2006Slide 15 (of 37) Overview Introduction/Background What is GIS, and what is its role in Public Health? Measuring Physical Activity Measuring the Built Environment ECOR Funded Research: Assessing the reliability and validity of the Multi-Sensor-Board for the direct measurement of physical activity, environmental characteristics, and the built environment Analysis Plan Suggestions/Questions

MEBI 591B Public Health Informatics Colloquium © Phil Hurvitz, 2006Slide 16 (of 37) Measuring Physical Activity Subjective Observation Self-Report Stanford 7-Day Activity Survey International Physical Activity Questionnaire (IPAQ) Travel Diaries Objective Pedometers Accelerometers New Generation Devices

MEBI 591B Public Health Informatics Colloquium © Phil Hurvitz, 2006Slide 17 (of 37) Measuring Physical Activity: Benefits & Drawbacks TypeBenefitsDrawbacks Subjective Observationdoes not require effort on part of subject accuracy varies by observer & instance high cost Self-Reportdoes not require observer low cost over-reporting common recall bias Objective Pedometerlow cost easy to use acceptable for free-living subjects not suitable for all populations no activity discrimination no location no temporal resolution Accelerometerno activity discrimination no location no temporal resolution New Generation Devices varies

MEBI 591B Public Health Informatics Colloquium © Phil Hurvitz, 2006Slide 18 (of 37) Measuring Physical Activity: New Generation Devices Intelligent Device for Energy Expenditure and Activity (IDEAA) sensors attached to skin (cumbersome) relative accelerometry of different body parts no locational capability no external environmental cues $4,000 per unit

MEBI 591B Public Health Informatics Colloquium © Phil Hurvitz, 2006Slide 19 (of 37) Measuring Physical Activity: New Generation Devices IDEAA: recognizable activities

MEBI 591B Public Health Informatics Colloquium © Phil Hurvitz, 2006Slide 20 (of 37) Measuring Physical Activity: New Generation Devices IDEAA: categorized activities by time

MEBI 591B Public Health Informatics Colloquium © Phil Hurvitz, 2006Slide 21 (of 37) Measuring Physical Activity: New Generation Devices Multi-Sensor Board UW/Intel invention, recent development single sensing unit with data logger (iPAQ, phone) easily worn measures multiple environmental data streams obtains XY locational data estimated $100 per unit cost in large manufacturing run

MEBI 591B Public Health Informatics Colloquium © Phil Hurvitz, 2006Slide 22 (of 37) Measuring Physical Activity: New Generation Devices Multi-Sensor Board On-board sensors: accelerometry audio IR / visible light high-frequency light barometric pressure humidity, temperature geophysical location Multivariate data stream can be interpreted as a number of common activities using Hidden Markov Model Classifiers Will be used in ECOR Pilot & Feasibility Study

MEBI 591B Public Health Informatics Colloquium © Phil Hurvitz, 2006Slide 23 (of 37) Measuring Physical Activity: New Generation Devices Multi-Sensor Board Activity Classifier (overall accuracy > 95%) Validated against videography SittingStandingWalkingJogging Walking up stairs Walking down stairs Riding a bicycle Driving car Riding elevator down Riding elevator up Sitting 89.8%38.5%0.5%0.4%33.4% Standing 10.1%50.8%1.4% Walking 0.1%7.4%97.7%5.2%2.5% Jogging 100.0% Walking up stairs 94.8% Walking down stairs 0.5%97.5% Riding a bicycle 3.3%99.6% Driving car 66.6% Riding elevator down 100.0% Riding elevator up 100.0% Classified Activity (by HMM) Precision Labeled Activities

MEBI 591B Public Health Informatics Colloquium © Phil Hurvitz, 2006Slide 24 (of 37) Measuring Physical Activity: New Generation Devices Multi-Sensor Board Classification of Activity 90-minute interval

MEBI 591B Public Health Informatics Colloquium © Phil Hurvitz, 2006Slide 25 (of 37) Overview Introduction/Background What is GIS, and what is its role in Public Health? Measuring Physical Activity Measuring the Built Environment ECOR Funded Research: Assessing the reliability and validity of the Multi-Sensor-Board for the direct measurement of physical activity, environmental characteristics, and the built environment Analysis Plan Suggestions/Questions

MEBI 591B Public Health Informatics Colloquium © Phil Hurvitz, 2006Slide 26 (of 37) Measuring the Built Environment What to Measure? Based on Research Question(s) GIS Data Sources Point Locations Buffer Measures Proximity Measures Where to Measure? Home-centered Frank et al Moudon et al Where does activity take place in real time?

MEBI 591B Public Health Informatics Colloquium © Phil Hurvitz, 2006Slide 27 (of 37) Measuring the Built Environment: A GIS Based Approach Point-centered Analysis of Location Any number of different data sets can be quantified Enumeration & relative proportion of different land uses Parcel density Street-block size Total length of sidewalk Number of intersections, lighted crosswalks Area and count of parks Distance to different built environment features We should quantify & analyze all locations that are experienced during the day, not only the home location Work & school environments may be key determinants of physical activity

MEBI 591B Public Health Informatics Colloquium © Phil Hurvitz, 2006Slide 28 (of 37) Measuring the Built Environment: A GIS Based Approach

MEBI 591B Public Health Informatics Colloquium © Phil Hurvitz, 2006Slide 29 (of 37) Measuring the Built Environment: A GIS Based Approach GIS analysis results for each location buffer (count) measures proximity measures

MEBI 591B Public Health Informatics Colloquium © Phil Hurvitz, 2006Slide 30 (of 37) Overview Introduction/Background What is GIS, and what is its role in Public Health? Measuring Physical Activity Measuring the Built Environment ECOR Funded Research: Assessing the reliability and validity of the Multi-Sensor-Board for the direct measurement of physical activity, environmental characteristics, and the built environment Analysis Plan Suggestions/Questions

MEBI 591B Public Health Informatics Colloquium © Phil Hurvitz, 2006Slide 31 (of 37) ECOR Funded Research Assessing the reliability and validity of the Multi- Sensor-Board for the direct measurement of physical activity, environmental characteristics, and the built environment MSB to capture Activity type Location Walkable-Bikeable Communities GIS Software Quantifying & analyzing the Built Environment

MEBI 591B Public Health Informatics Colloquium © Phil Hurvitz, 2006Slide 32 (of 37) Overview Introduction/Background What is GIS, and what is its role in Public Health? Measuring Physical Activity Measuring the Built Environment ECOR Funded Research: Assessing the reliability and validity of the Multi-Sensor-Board for the direct measurement of physical activity, environmental characteristics, and the built environment Analysis Plan Suggestions/Questions

MEBI 591B Public Health Informatics Colloquium © Phil Hurvitz, 2006Slide 33 (of 37) Analysis Plan MSB activity & location Validity tests against diary (real-time location & activity), IPAQ (self-reported physical activity summary) WBC location analysis of Built Environment Data overload? 15 h * 60 min/h * 60 s/min * 7 d * 40 subjects = 15,120,000 data points

MEBI 591B Public Health Informatics Colloquium © Phil Hurvitz, 2006Slide 34 (of 37) Analysis Plan Sampling strategy for data reduction without loss of variability 10% sample → 1.5 million data points (time or distance?)

MEBI 591B Public Health Informatics Colloquium © Phil Hurvitz, 2006Slide 35 (of 37) Analysis Plan This will be the first study to measure objectively both physical activity types and Built Environment in a real-time, real-world setting with free-roaming individuals Statistical associations? Activity types/intensities & Built Environment types? What do we gain if a pattern is discovered? Policy recommendations Quantitative urban design guidelines A new “gold standard” for measurement of physical activity in real-time

MEBI 591B Public Health Informatics Colloquium © Phil Hurvitz, 2006Slide 36 (of 37) Overview Introduction/Background What is GIS, and what is its role in Public Health? Measuring Physical Activity Measuring the Built Environment ECOR Funded Research: Assessing the reliability and validity of the Multi-Sensor-Board for the direct measurement of physical activity, environmental characteristics, and the built environment Analysis Plan Suggestions/Questions

MEBI 591B Public Health Informatics Colloquium © Phil Hurvitz, 2006Slide 37 (of 37) Suggestions/Questions Phil Hurvitz gis.washington.edu/phurvitz