====== SUMMARY ======

Title: Tidal dispersion in short estuaries

Principal investigator: 
Michael Weir

Co-investigators: 
Maya Lozinsky, Scripps College
Di Jin, WHOI

Contact:
Michael Weir, mweir@whoi.edu

Size:
1400 KB

File format:
csv

Description:
The files included in this repository will facilitate replication of the choice modeling and summary statistics presented in the manuscript. The “choice_model.csv” file contains all parameters necessary to replicate the choice model results including the consumer surplus calculations following the methods described in the manuscript. Necessary assumptions are elaborated below. Similarly, the file “summary_stat_data.csv” contains the variables summarized in the summary statistics table of our manuscript. 


====== MODEL DATA ======
file: choice_dat.csv

Data description:
We estimate a random parameter logit ("RPL") model to capture the marginal change in utility given the different OTZ harvest scenario attributes. We use maximum-likelihood methods to numerically evaluate the choice probability integral using 5000 Sobol draws. Our specification for the empirical model captures preferences for the expected value of a scenario outcome as determined by the corresponding likelihood level for a given alternative. This specification is grounded in expected utility theory which assumes that utility from a particular outcome is multiplied by the probability of that outcome. Further, preferences over uncertainty itself are not theoretically justified in this framework which limits its value for estimating welfare. Aside from the cost coefficient, each coefficient is assumed to follow a normal distribution which allows us to account for unobserved individual heterogeneity without imposing undue restrictions on the population distribution for any given parameter. We modeled the cost coefficient as a negative log-normal distribution. 

File name:
The following naming convention is adopted for model parameters.
	"{name}_{alternative}"
where
	{name}: variable name
	{alternative}: 1,2,3; corresponding to the associated choice experiment alternative

those variables below listed without the {alternative} qualifier are not specific to choice experiment alternatives.

Variables (24 variables in total):
Response.ID - unique identifier for individual survey respondent	
block - assigned block of choice experiment questions
ques - question number within each block
IOLS_total - total score on IOLS assessment out of 14.
cost_{alternative} - presented cost of policy scenario
EV_food_{alternative} - expected value of food provided by OTZ harvest policy
EV_emissions_{alternative} - expected value of emissions captured given OTZ harvest policy
choice	- alternative selected
sq_{alternative} - indicator variable to designate the status quo alternative. sq_{1,2} are always 0 while sq_3 is always 1.
Oliterate - an indicator variable equal to 1 if the IOLS_total divided by 14 is greater than or equal to .6
lit_EV_food_{alternative} - interaction term between Oliterate and EV_food_{alternative}	
lit_EV_emissions_{alternative}	- interaction term between Oliterate and EV_emissions_{alternative}																		
====== SUMMART STATISTIC DATA ======
file: summary_stat_data.csv

Data description: These data include demographic and descriptive information collected from responses to the survey. These data were used to generate the summary statistic table presented in our manuscript.


Variables:
Response.ID - unique identifier for individual survey respondent	
clim_change - response to question capturing climate change beliefs	
risk_tolerance	- self-reported tolerance to risk ranging from 1 (does not take risks) to 10 (very risky)
age - in years	
gender- self-reported (Male/Female) Other options were presented but not selected
educ - highest education achieved
Asian.race - indicator equal to 1 if identifying as Asian
Native.Hawaiian.or.Other.Pacific.Islander.race	- indicator equal to 1 if identifying as Native Hawaiian or other Pacific Islander
Black.African.American.race - indicator equal to 1 if identifying as Black/African-American
White.race- indicator equal to 1 if identifying as White
Hispanic.Latino.race - indicator equal to 1 if identifying as Hispanic or Latino
American.Indian.Alaska.Native.race - indicator equal to 1 if identifying as American Indian or Alaska Native
Other...Write.In.race - indicator equal to 1 if identifying as Other race
Prefer.not.to.answer.race = indicator equal to 1 if respondent preferred not to answer
Other...Write.In.race.1	- text response if identifying as Other race
income	- binned income response
IOLS{number}_score : scoring taking the values {0,.5,1} based on response. {number} ranges from 1-14 and correlates directly with the IOLS questions used and described in the manuscript. Respondents received a full point for a correct answer and a half point if selecting at least one but not all correct responses for a “select all that apply” question type.