Vote counting is the most primitive but simplest and most intuitive method of meta-analysis. In this approach, significant features are first selected based on some criteria (e.g. adjusted P < 0.05 and same direction of fold changes) for each data set.
The vote for each features can then be calculated by counting the total number of times it occurs as significant across all data sets. This method is statistically inefficient and should be considered as a last resort in situations when other meta-analysis methods cannot be applied.