Regression is a statistical technique that allows economists and financial analysts to understand how a change in one or more independent (explanatory) variables might result in a change in a dependent variable. This is done by fitting a best-fit line to the data and assessing how the data is dispersed around that line. For example, if a prediction were being made about the impact of rising interest rates on stock prices, a regression model could show how significant changes in the interest rate would likely lead to corresponding changes in stock prices.

Regression allows analysts to predict the value of an asset or to assess the relationships between different market variables. For example, an analyst could use a regression to test a hypothesis that suggests stock prices and dividend payments of a certain company follow a particular pattern. If the data supported the hypothesis, then the analyst could use the regression to forecast what stock prices and dividend payments could be expected in the future.

The application of regression in economics and finance is widespread and its usefulness is acknowledged. However, in order for the results obtained through regression to be properly interpreted, it is important to ensure that several assumptions are met. These assumptions involve the structure of the data and the model itself, including: linearity between the variables; normality of error terms; homoscedasticity; and the absence of multicollinearity.

Moreover, there are also statistical tests, such as the ANOVA, which can be carried out to testing the validity of the model, specifically of its overall fit. These tests measure the difference between the observed values and the values that the model predicts and assess whether this difference is due to random chance rather than a systematic pattern.

In conclusion, the use of regression in economics and finance is often quite powerful and can provide valuable insights. Yet, for the results produced by regression to be both valid and reliable, it is crucial for several key assumptions to be met and for the model structure to have been appropriately tested and verified.