1. Measuring Food Access in Ada County
Carl B. Anderson 2nd Year MCRP Student Public Policy Research Center

2. Furthering our research
The PPRC
Other models
Methodology
Findings
Furthering our research
Overview

3. The Public Policy Research Center
The public policy research center is a non-partisan, interdisciplinary research center actively engaged in public policy and administration research on a broad range of complex and dynamic issues.
As many of you likely already know, food accessibility issues face many communities and contribute to multiple issues such as childhood obesity, heart disease, and diabetes.
There are many factors underlying this issue such as the location of one’s home in relation to food outlets that provide healthy food options.
The USDA defines a food desert as “ urban neighborhoods and rural towns without ready access to fresh, healthy and affordable food.”
- Instead of supermarkets and grocery stores, these communities may have no food access or are served by fast food restaurants and convenience stores.

4. Food Access Research Atlas
Let’s you know you are in a food desert
Does not tell you what type of food is available
- Based on a 5. km grid.
Low income census tracts where a significant number or share of residents is more than ½ mile (urban) and 10 mile (rural) from the nearest super market.
Under this model they qualify as a food desert if they are both low-income & low-access.

5. Methodology Used North American Industry Classification
Verified with COMPASS data
GIS network analysis for real world network
Kernel density to measure average distance to food
Differs form most other food access measures, which measure distance as the crow flies. There are studies that have included transportation networks. (such as Manhattan block equivalents to measure travel distance in Detroit & different modes of transportation to measure time to outlet. Ours allows us to take into account natural barriers such as rivers, to force alternate paths.
Used the NAICS to categorize and locate the types of food outlets available
Mapped food outlets & verified addresses with data from metropolitan planning organization (COMPASS)
Determined real world distance to outlets, from parcels to outlets, using network analysis along street networks.
a. Including sidewalks and crosswalks into a walking network, employing hierarchies.
Using spatial statistic tool kernel density (calculates density measures)
Average distances to food outlets within a defined search radius of .5 miles
Where food access for neighbors is more heavily weighted in the average, then applies smoothing function to measures.
Resulting map shows residential distance to outlets relative to their neighbors.

6. Distance to food outlets in Ada County, Idaho by outlet type.
Residences within ½ mile 
Residences within 1 mile
Residences within 3 mile 
Average Distance
(all Ada County) (miles ) 
Limited Restaurant  
31381 (23.5%) 
80466 (60.3%) 
(95.2%) 
1.14 
Restaurant  
28398 (21.3%) 
70528 (52.9%) 
(93.7%) 
1.25 
Groceries  
20012 (15%) 
64158 (48.1%) 
(96.3%) 
1.21 
Gas station/Convenient store  
6057 (4.5%) 
25347 (19%) 
(76.3%) 
2.57 
Supermarket  
1402 (1.1%) 
7218 (5.4%) 
62620 (46.9%) 
3.70 
Closest Distance to any type  
43796 (32.8%) 
93595 (70.1%) 
(97.9%) 
0.88 
Total residences in study area: 133,437  

7. Ada County
Fast-food or Gas Station
Groceries or Supermarket

8. Vista Neighborhood
Fast-food or Gas Station
Groceries or Supermarket

9. Limitations Have not yet included economic factors
Did not include mobile food markets
Did not include informal food sources (community gardens, friends and relatives, mobile food markets)

10. Furthering Our Research
Identify measures that include work commute
Identify programming that creates access to healthy food sources
Interactive map

11. Contributions Thomas Wuerzer Ph.D. Vanessa Crossgrove Fry
Community and Regional Planning
Vanessa Crossgrove Fry
Assistant Director of the Public Policy Research Center
Eric Lindquist Ph.D.
Director of the Public Policy Research Center