Invägning

Invägning is a term used to describe the process of assigning weights to items, observations, or components in order to influence their impact on a calculation, decision, or measurement. The concept is widely used across disciplines to reflect relative importance, frequency, probability, or quality when aggregating data or forming summaries. Invägning is often referred to as weighting in English.

Applications

Statistics and data analysis: weighted means, weighted regression, survey weighting, design weights, and post-stratification weights to adjust for unequal selection probabilities or non-response.

Quality control and manufacturing: weighing ingredients, raw materials, and batch components to ensure correct formulation or to monitor deviations.

Finance and economics: weighing assets in a portfolio or in indices; calculating weighted averages of indicators.

Research and policy evaluation: combining indicators into composite indices with weights that reflect importance or reliability.

How weights are chosen

Weights can be determined from theoretical considerations, empirical data, or user judgment. They may be normalized (summing to one) or scaled for interpretability. In data analysis, inappropriate weighting can bias results, so sensitivity analysis is often recommended.

Relation to related concepts

Related terms include viktning, and viktat medelvärde (weighted mean), as well as other weighted statistics.

Limitations

Invägning introduces subjectivity and requires transparent justification, especially in policy or research reporting. Proper documentation of how weights are derived and tested helps maintain credibility and reproducibility.