ROC Signal technical indicator bug in scan engine?

Kevo

I was using the ROC Signal technical indicator in the scan engine to see if ROC was above or below its signal line. I think ROC Signal has a bug in the scan engine. Now that I realize this could be a bug, I made a change. I'm now applying an EMA to the ROC, which does correctly work. The Rank By clause is very helpful. Without it, I would not have discovered this. You can see that the scan engine returns 1.24, but the chart shows 0.13. Here are details of the bug:

markd

Your scan asks for an EMA, the chart is displaying and SMA.

If you remove the ",20" under Parameters, and use "Overlay", instead, you will see the difference.

Kevo

Oh. I see what's going on. The chart returns an EMA using the second parameter. The scan engine returns an SMA using the second parameter. The chart label says "MA", which does not specify EMA or SMA. This should have been taken as a clue that the scan engine may not return an EMA like the chart does.

On weekly charts, checking above/below ROC Signal was one way I was checking trend or at least positive/negative momentum.

Thank you for the help markd.