valgsmodeller

Valgmodeller are mathematical and statistical frameworks used to analyze and predict how individuals make choices among a finite set of alternatives. They are grounded in random utility theory, where each option provides a latent utility and the chosen option is the one with the highest perceived utility. These models are employed in disciplines such as econometrics, marketing and political science to study consumer decisions, transportation mode choice, or voting behavior.

Common forms of valgmodeller include:

- Multinomial logit (MNL) and conditional logit, which relate the probability of choosing an option to its attributes and the individual’s characteristics.

- Nested logit, which relaxes the independence of irrelevant alternatives (IIA) by allowing correlated choices within groups.

- Multinomial probit, which uses a multivariate normal error structure to capture correlations between choices.

- Mixed logit (random parameters), which introduces random taste variation across individuals and can approximate complex substitution patterns.

- Latent class models, which segment the population into groups with distinct decision rules.

Data for valgmodeller typically consist of individuals, options, and attributes describing each option as well as observed covariates for the decision maker. Estimation is usually done by maximum likelihood or Bayesian methods. Model fit is assessed through out-of-sample prediction, information criteria, and tests of goodness-of-fit, with attention to issues such as IIA, endogeneity, and scale.

Applications are broad, including forecasting electoral outcomes and party choice, analyzing consumer product selection, transportation mode choice, and policy evaluation. Software tools commonly used include R (packages for logit and probit models), Python libraries, Stata, and specialized packages like Biogeme.

Valgmodeller provide a principled approach to understanding decision making under alternative options and to predicting how changes in attributes or policies may influence choices.