making baseline hierarchical bayes models for CIVA #253
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preparing meeting with jeff dotson 1. goal: illustrating essential heterogeneity to bayesian entrepreneurship scholars (#234)hypothesis: due to lines of research on choice
Essential heterogeneity extends beyond simple heterogeneity by recognizing that variations in effects are not just random differences between units, but are systematically related to the units' choices. This correlation between choice and effect poses significant challenges for estimation, invalidating traditional methods like instrumental variables or simple regression approaches. In the context of strategy research, such as studying diversification's impact on firm performance, essential heterogeneity acknowledges that firms choose to diversify based on their expected benefits. This necessitates a more complex modeling approach that jointly considers both the choice to adopt a strategy and its subsequent effects. Bayesian methods, particularly hierarchical models, are well-suited for this task as they allow researchers to explicitly model the data-generating process, including the decision-making mechanism and its relationship to outcomes. This approach provides a more accurate representation of strategic decision-making and its consequences, overcoming the limitations of methods that assume randomization or independence between choices and their effects.
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info on SAFEcurrent practice is post money safe with valuation cap 🧢 without discount according to here I think SAFE which started from paul graham's spirit of high resolution funding, increasing the optimization dimension based on conversational inference is a good place to start.
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after getting jeff's input, will continue with getting vikash's input for CIVA baseline models cld to ask vikash for his input |
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using Startup Valuation Model with jeff cld
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Model Structure:
Level 1 (Individual Startup):
log(Valuation_it) = β_0i + β_1i * Stage_it + β_2i * Revenue_it + β_3i * Employees_it + ε_it
Where:
i = individual startup
t = time period
ε_it ~ N(0, σ^2)
Level 2 (Startup-specific parameters):
β_0i = γ_00 + γ_01 * Industry_i + γ_02 * FounderExperience_i + u_0i
β_1i = γ_10 + γ_11 * Industry_i + u_1i
β_2i = γ_20 + u_2i
β_3i = γ_30 + u_3i
Where:
u_0i, u_1i, u_2i, u_3i ~ MVN(0, Σ)
Prior Distributions:
γ_00, γ_01, γ_02, γ_10, γ_11, γ_20, γ_30 ~ N(0, 10)
σ^2 ~ InvGamma(0.01, 0.01)
Σ ~ InvWishart(I, 5)
This model structure allows for:
Firm-specific effects: Each startup has its own intercept and slopes, capturing heterogeneity.
Industry effects: The impact of industry on both the baseline valuation and the effect of funding stage.
Founder experience: Incorporated at the startup level to affect baseline valuation.
Time-varying covariates: Stage, Revenue, and Employees can change over time for each startup.
Correlated random effects: The multivariate normal distribution for the u terms allows for correlation between the random effects.
Captures heterogeneity across startups and industries.
Allows for both startup-specific and population-level inferences.
Can handle unbalanced panel data (startups observed at different time points).
Incorporates prior knowledge through the prior distributions.
Can be easily extended to include more covariates or levels as needed.
BMEV with Marr3 cld reports
inv_wishart
function is not built into Gen, so we might need to use Stan.Beta Was this translation helpful? Give feedback.
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