Coqui frogs and the decline of property
values on the island of Hawaii
Kimberly Burnett
University of Hawaii at Manoa
Department of Economics
Brooks Kaiser
Gettysburg College/UH Manoa
Department of Economics
Project overview

Objective: Does the presence of the frog on or near a property
result in a decline in that property’s value?

NOTE! This study considers only impact on property value,
thus should be considered a lower bound estimate of actual
economic costs from the frog

Analysis does not include:


Impacts to agriculture, horticulture industries
(double hit in reduced sales and increased costs)
Any potential ecological damages
Model

Built a model to explain Hawaii County property prices that depends on:

Square footage, how many rooms

How many acres

Strength of market (proxy with mortgage rate)

Year of sale

District (Puna, S. Hilo, N.Hilo, Hamakua, N. Kohala, S. Kohala,
North Kona, South Kona, Kau)

Zoning class (agriculture, apartment, unimproved residential,
improved residential, conservation, industrial, resort, commercial)

Finally, presence or absence of frog (within 500 m of the property)
Data


Hawaii County
Sample:




50,033 real estate transactions between 1995-2005
Omit sales that fall within the lowest or highest 1% of prices
37,228 properties, each changes hands 1–6 times (average 1.2 times),
for a total of 46,405 transactions
Frog complaints registered to USDA/APHIS Wildlife Services


Use GIS to match verified frog complaints 1997-2001 to property
transactions
Generate indicator variables for whether property is within 500m of
previous complaint
Outlier,
excluded
(over 100,000 ac)
District Level Summary Statistics
District
Number of Average % of properties within
Transactions
500 m of frog complaint
Puna
20,914
17%
South Hilo
4,163
37%
North Hilo
412
0
Hamakua
683
2%
N. Kohala
1,452
1%
S. Kohala
4,595
21%
N. Kona
7,871
33 %
S. Kona
1,427
14%
Kau
5,049
0
Puna Close-up
Transactions
Frogs within 500 m
Frogs within 800 m
Results

Find that coqui frogs do impose localized damages to real
estate values

The per-transaction reduction in value when frog complaints
have been lodged within 500m appears to be about 0.16%,
holding constant all other characteristics

Consider for a moment…0.16% may sound small, but
Hawaii’s real estate is valuable!
Hawaii County

Median value of single family home: $411,500
(UHERO 2006)

34,175 owner-occupied housing units (DBEDT 2000)

0.16%* $411,500 = $658.40 per property* 34,175 homes =
$22.5 million
Potential impacts to neighbor islands

Keep in mind…real estate values on Maui and
Oahu are considerably higher than the Big Island

Maui County


0.16%*$703,500 = $1,125 per property*25,039 =
$28.2 million
Honolulu County

0.16%*$632,200 = $1,012 per property*156,290 =
$158.1 million
Conclusions

The presence of the coqui frog in Hawaii county has already
begun to lower property values

An official complaint of the frog within 500m reduces
property values on average 0.16%

If the frog spreads across all residential properties, direct
damages to property values are estimated at a minimum of
$22.5 million for Hawaii county, as much as $208 million for
the state
1997-2001
1997-2007
Mahalo funders and friends
James Roumasset (Principal Investigator), UHM Economics
Will Pitt, USDA/APHIS/WS
Mindy Wilkinson, DLNR/DOFAW
Earl Campbell, USFWS