The "average variance extracted" measures the amount of variance that is captured by the construct in relation to the amount of variance due to measurement error and can be calculated using the following formula:
AVE=(summation of squared factor loadings)/(summation of squared factor loadings) (summation of error variances) (Fornell & Larcker).

If the average variance extracted is less than 0.50, then the variance due to measurement error is greater than the variance due to the construct. In this case, the convergent validity of the construct is questionable.

There's no provision of AVE in SPSS. Calculate it manually:
1. Run EFA and note the factor loading of statements in every factor.
2. Take average of these factor loadings and square it. This is AVE.