Spatial accessibility Study

A study of spatial accessibility to health facilities for elderly people in metro Atlanta

using a categorical multi-step floating catchment area method

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Presenter: Zhaoying Wei

Committee Member:Xiaobai Yao(Chair)Lan MuSara Wagner

Outline

• Introduction

• Research question

• Literature Review on Accessibility

• Research Objectives

• Research Design• Method• Case study

• Results

• Limitation 2

IntroductionElderly population

• A defining global issue: population ageing

• Concerns have emerged in the area of elderly health care

• 65 years and over: (2010 Census)

US 40,267,984 13% GA 1,032,035 10.7%

• Limited regenerative abilities , suffer mobility, health and disability problems

• Placing a strain on government finances and health care facilities

• eligible for Medicare regardless of income and assets3

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Introduction

• Medicare is the federal health insurance program for people who are 65 or older, some disabled individuals under the age of 65, as well as patients with end-stage renal (kidney) disease.

• Not covered (the official US government site for Medicare) Non-skilled personal care

Routine dental or eye care

Dentures

Cosmetic surgery

Acupuncture

Hearing aids and the exams for fitting them

Routine foot care

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Medicare

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1. What is an appropriate method of measuring accessibility to health facilities for people who are eligible for Medicare?

2. What is the current situation of accessibility to health facilities for people who are eligible for Medicare in Atlanta?

Research question

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Review on accessibilityWhat is accessibility?

• Accessibility: the relative ease by which the locations of activities, such as work, shopping and health care, can be reached from a given location (BTS 1997)

• Access to health facility in a given location : the measurement of opportunities available to that health facility within certain distance or travel time (Aday and Andersen 1974)

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classification

• Spatial Access: varieties across space due to the uneven distribution of providers and consumers (spatial factors)

• Nonspatial Access: varieties among population groups because of their different socioeconomic and demographic characteristics (nonspatial factors)

• Focus on the method for measuring spatial accessibility to health care facilities

• not consider race and income disparity due to data unavailability

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Review on accessibility

Current Methods

Pros• Catchment Area: distance impedance

• Sum of facility to population ratio:

• Selection Weight

competition within one type of health facility

Two-step floating catchment

area(2000)

Enhanced two-step floating catchment

area(2009)

Three-step floating catchment area(2012)

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Demand

upply S

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Current Methods

Cons• the catchment size could be more flexible

• only consider competition within the same group

Categorical multi-steps floating catchment area diverse catchment sizes (step 1-4)

competition ratio to involve competition from other groups (step 4)

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Research Objectives

1. Propose a categorical multi-step floating catchment area (CMSFCA)method

2. Conduct a case study for people who are 65 and over in metropolitan Atlanta MSA.

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What’s an appropriate

method?

What’s the current

situation?

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Research Design

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1.

• Develop a categorical multi-step floating catchment area method

2. • A case study in Atlanta MSA

using CMSFCA method

Method

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Categorical multistep floating catchment area method

Various Catchment Sizes

• Step 1: selection weight

• Step 2: facility to population ratio

• Step 3: general accessibility to facilities

• Step 4: categorical accessibility

NEW STEP

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Python & Network Analyst

Health facility type Catchment

Size (min)

Distance impedance

coefficient β

Offices of Physicians 60 0.11

General Medical and

Surgical Hospitals

90 0.08

Homes for the elderly 120 0.05

Nursing care facility 120 0.05

MethodStep 1——Determination on The Likelihood of Selecting Health Facility at Population Locations

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★ census tract centroid

Health facility

dij : real travel time

β : distance friction parameter

Selection Weight13

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Competition within group

negative exponential function

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MethodStep 2——Obtaining The Ratio of Medical Capacity of Health Facilities to Demand of Elderly Population at Health Facility Locations

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Health facilitymedical capacity– employee number

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Supply/selection-weighted Demand



Selection Weight

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MethodStep 3——The General Spatial Accessibility Without Including Competitions Between Groups

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Health facility

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Sum of selection-weighted facility to population ratio

Selection Weight

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MethodStep 4——The Categorical Spatial Accessibility Including Competitions Between Groups

• Diverse subgroups usually compete with each other for opportunities： e.g. hospital vs offices of physician

nursing care facilities vs homes for the elderly

• Assumption: no competition between acute care services and long term care services

• Preference score: impact choices of visiting health facilities

e.g. people’s knowledge of health facility; the quality of service provision;

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Competition ability between groups

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MethodStep 4——The Categorical Spatial Accessibility Including Competitions Between Groups

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Competition ability between groups

PR=1dij : real travel time


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Case studyStudy area

• Atlanta metropolitan

statistical area (MSA)

• 28 counties, 946 census tracts

• Total people: 5,268,860

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Case studyDemand Data: elderly population

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Demographic Data

• Georgia Census 2010 Summary File 1

• Elderly population(>=65):

471,753 , 9%

Corresponding geographic boundaries

• 2010 Census TIGER/Line dataset

Mobility problem

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Case studySupply Data: Health Facilities for elderly people

Health facility points

• extracted from 2008 Business point from MapInfo

• North American Industry Classification Code (NAICS) 2010 edition

• Facility capacity : actual number of employees

NAICS Code Label Number621111 Office of physicians (except

mental health specialist) 234

622110 general medical and surgical hospitals

5414

623312 home for the elderly 388623110 nursing care facilities 742

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Case studySupply Data: Health Facilities for elderly people

Health facility points

• Offices of Physicians:

data clearing

(manual editing)

• 4336 remained (80%)

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Case studyMeasuring travel distance

Distance parameter : travel time

• road network: 2005

• Diverse catchment sizes:

Offices of physicians: 60 min

Hospitals: 90 min

Homes for the elderly and nursing care

(long term): 120 min

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Measuring travel distance

Case study

• Origin-Destination Cost Matrix

•Total_Cost： travel time (min) between

origin and destination pairs

Hospitals elderly population

Offices of physicians

Nursing care facilities

Homes for the elderly 24

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ResultsStep 4——hierarchical spatial access (acute care)

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General Categorical3

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General Categorical3

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Step 4——hierarchical spatial access (acute care)

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Results39

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Limitation

• appropriate function for the distance decay weights, beta

• suitable catchment size

• use employee number as medical capacity

• overlap of hospitals and physicians

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Thank you !Questions?

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Spatial accessibility Study

Technology

Transcript of Spatial accessibility Study