We investigate the effects of manifest residual variances, indicator communalities, and sample size on the χ2-test statistic of the metric measurement invariance model when the model is misspecified, i.e., there is at least one population loading that violates metric measurement invariance. First, we demonstrate the choice of the scaling method does not affect the model’s χ2-test statistic. Afterward, we demonstrate that the χ2-test statistic relates inversely to manifest residual variances, whereas sample size and χ2-test statistic show a positive relation. Moreover, we consider indicator communality as a key factor for the size of the χ2-test statistic. In this context, we introduce the concept of signal-to-noise ratio as a tool for studying the effects of manifest residual variance and indicator communality and demonstrate its use with the example. Finally, we discuss the limitations and the practical implications for the analysis of metric measurement invariance models.