Participation thresholds
For 38.4 < K ≤ 43.2 at ρR = 0, the farmer participates only under the fixed rule. The realized-profit comparison therefore reverses because the chosen-rule option has no trade.
COMSCI–ECON 206 · PS1
Farmer–Intermediary Margin Lab
How do fixed versus intermediary-chosen margin rules shape farmer participation and modeled household access? Explore the assumptions behind the comparison.
Interpretation: All numbers on this page are generated by a synthetic model. No behavioral study has been run. The reputation response defaults to zero; a nonzero setting is only a scenario until estimated from the proposed study.
Explore a scenario
Higher K makes farmer participation harder. The model's baseline cutoffs are 43.2 under a fixed rule and 38.4 under a chosen rule.
A proportional demand shifter applied only to the verified-information cells. Keep at zero until a treatment effect is estimated.
Choose which information condition to use for the rule recommendation. The full four-cell comparison remains visible below.
The recommendation changes with the outcome that the decision maker values.
The four comparison cells
The information treatment and margin rule are separate dimensions. Listed household price, product identity, quality evidence, quantity, and delivery are held fixed in the proposed vignette; the table reports model quantities, not observed household purchases.
| Seller-history information | Margin rule | Margin m | Effort e | Completed units* | Farmer net* | Intermediary profit* | Participation |
|---|
*Conditional model outputs after the farmer's participation decision. Completed units are an access proxy, not observed purchases, household welfare, or consumption inequality.
Where the ranking can change
When both rules trade
Under the baseline assumptions, the fixed rule generates more modeled completed units and farmer net earnings; the chosen rule generates more intermediary profit. These rankings depend on the assumed functional forms and parameters.
Use the coordination-cost slider to see the participation boundary. Use the ρR slider only for sensitivity scenarios until experimental estimates are available.
Planned test: separate reputation from price and quality perceptions
The proposal's 2 × 2 behavioral study varies (1) fixed versus intermediary-chosen margin rules and (2) sparse versus verified seller-history information. The household-facing listed price, product identity, quality evidence, quantity, and delivery stay the same across cells.
Measure household responses
Record purchase choice, trust, perceived price fairness, expected product quality, and willingness to pay. If the history signal changes perceived price or quality, analyze those as competing pathways rather than assigning the whole response to trust.
Connect the study to the model
Estimate the verified-history effect on purchase probability, translate it into the model's ρR demand shifter, then rerun the 2 × 2 comparison and coordination-cost sensitivity. Until then, ρR = 0 is the baseline.