Squaring makes every contribution nonnegative, so positive and negative residuals cannot cancel one another in the total. It also makes larger discrepancies contribute more than smaller ones, allowing the measure to reflect the overall size of prediction errors. This mathematical treatment is central to least-squares estimation and to evaluating how closely a model matches observed data.
Least-squares estimation treats model parameters as adjustable quantities and selects the values that produce the smallest SSE for the available observations. The resulting parameter estimates represent the model configuration with the lowest total squared discrepancy under that criterion. This connects the numerical error measure directly to fitting regression models and choosing parameter values systematically.
SSE is not automatically comparable across datasets with different numbers of observations or measurement scales. Adding observations can increase the accumulated total, while changing the units of the measured outcome changes the sizes of the residuals and their squares. Consequently, interpretation should account for whether models were evaluated on the same data and using the same scale.
Yes, SSE can support model comparison when the models are applied to the same data and their predictions concern the same measured outcome. The model with the smaller total represents less squared discrepancy under that comparison. A raw SSE value should not be interpreted in isolation, because its magnitude also depends on sample size and measurement scale.
First, obtain the observed value and corresponding model-predicted value for every observation. Next, subtract each prediction from its observation to obtain the residual, square each residual, and add the squared values together. The final sum provides the model's total squared discrepancy for that dataset, which can then support goodness-of-fit assessment or comparison.
In regression, SSE helps evaluate how well a fitted model reproduces observed outcomes while using its predictors. A smaller total indicates less discrepancy between predictions and observations for the evaluated data. Comparing SSE across suitable models can therefore help assess whether one predictor-based specification explains variation more effectively, provided the models use the same dataset and outcome scale.