Hi! I implemented a discrete choice experiment to model cassava planting material alternative choice. In my questionnaire, I presented each respondents with 16 choice experiments or choice sets with each choice set having 2 alternatives or choices with an opt-out option. The explanatory variables are the attributes (11 in total) of cassava planting material with varying attribute levels that have randomly fitted between 2 alternative. With this, I am fitting a conditional logit model. In my data set, some explanatory variables are represent by dummy variables while others were categorical variables with up-to 3 categories.
Since each choice experiment has 2 alternative options and an opt-out option, each choice set has 11 rows and each respondent was presented with 16 choice sets.
(The sample of the original attribute and sample data is show below) Attributes of the cassava planting material
| Cassava stem attributes | Alternative A | Alternative B | Alternative C |
| Yield | Low (<20 Tons/Ha) | Moderate (20-30 Tons/Ha) | High (>30 Tons/Ha) |
| Disease tolerance | Susceptible | Tolerant | |
| Raw taste | Bitter | Sweet | |
| Cooked taste | Bitter | Sweet | |
| Mealiness | Hard | Mealy | Watery |
| Maturity | Late (>18 months) | Intermediate (13-18 months) | Early (6-12 months) |
| Seed availability | Scarce | Available | Plenty |
| In soil longevity | Short term (Up to 1 year) | Long term (Above 1 year) | |
| Shelf-life of stakes | Low shelf-life | High shelf-life | |
| Suitability in crop systems | Suitable | Not suitable | |
| Price | 10,000 | 27,000 | 40,000 |
| Which one would you choose? |
|
1. Yes 0. No | 1. Yes 0. No |
| Attribute | Alternative 1 | Alternative 2 | Alternative 3 |
| Yield | Low (<20 tons/ha) | Low (<20 tons/ha) | Opt out |
| Disease tolerance | Susceptible | Susceptible | |
| Raw taste | Bitter | Bitter | |
| Cooked taste | Sweet | Sweet | |
| Mealiness | Mealy | Mealy | |
| Maturity | Late (>18 months) | Intermediate (13-18 months) | |
| Seed availability | Available | Plenty | |
| In soil longevity | Short term (Up to 1 year) | Short term (Up to 1 year) | |
| Self-life of stakes | Short term | Short term | |
| Suitability in crop system | Suitable | Suitable | |
| Price | 10000 | 27000 | |
| Question: Which alternative do you prefer? | 1. Yes 0. No | 1. Yes 0. No |
| Pid | Choice_Set | Choice_Response | Yield | Disease_tolerance | Rawtaste | Cookedtaste | Mealiness | Maturity | Seed_availabity | Insoil_longevity | Shelflife_stakes | Suitability_crop sys | Price (UgX) |
| 1 | 1 | 1 | Moderate (20-30 t/ha) | Tolerant | Sweet | Sweet | Mealy | Late (>18 months) | Plenty | Long-term (above 1 year) | High | Not suitable | 27,000 |
| 1 | 1 | 0 | Moderate (20-30 t/ha) | Tolerant | Sweet | Sweet | Hard | Intermediate (13-18 months) | Scarce | Long-term (above 1 year) | High | Suitable | 27,000 |
| 1 | 2 | 0 | High (>30 t/ha) | Susceptible | Bitter | Sweet | Watery | Late (>18 months) | Plenty | Short-term (Up-to 1 year) | Low | Suitable | 10,000 |
| 1 | 2 | 1 | High (>30 t/ha) | Tolerant | Bitter | Sweet | Watery | Late (>18 months) | Plenty | Short-term (Up-to 1 year) | High | Suitable | 27,000 |
| 1 | 3 | 1 | Moderate (20-30 t/ha) | Tolerant | Sweet | Sweet | Mealy | Late (>18 months) | Available | Long-term (above 1 year) | Low | Suitable | 27,000 |
For clogit to work, I tried select choice set as the grouping variable but stata shows it has more than one. I want to establish the attributes preferred by the respondents and later determine the willingness-to-pay and potentail demand, how do i proceed? I really need this help! Thank Stephen Angudubo
