Just stumbled on this when looking for something else. I am currently working on a study that uses the slope function also. My “criteria” is 4 degrees for a bullish bias and -4 degrees for a bearish bias. The issue I have is that when you get into the higher priced stocks this “4 or -4” no longer works. I think this is due to the y-axis (price) not being “equal size” as compared to the x-axis (time).
Here is an example of what I think would be the most optimal scenario…could be totally wrong. Since there are 390 minutes in the trading day, the y axis would have to be $390 tall. If it’s way higher than you get a higher angle, if it’s lower than a lower angle.
Another example. If I have a stock that trades for $50 and the slope is 4 degrees (using the ATan function) then the stock should be ripping. If I use that same function on a $30,000 stock, 4 degrees is basically flat. I actually went and looked at BRK/A and it showed my slope at 90. In troubleshooting I think the reason why is because the “boxes on the graph paper” are nowhere near equal unless your stock price is in that $390 range. (45 degrees would be $1 per minute if I remember correctly, it was a week or two ago)
Final example. If I want to measure the slope of miles to minutes and anything over 45 degrees is a positive result than my most optimal chart would be 1, 2, 3, 4, 5 miles etc on the y axis and 1, 2, 3, 4, 5 minutes on the x axis. If I suddenly switch the y axis to 1200, 1800, 2400, 3000, 3600 than my slope is now going to look much different. (Makes sense in my head)
The true equation for slope as I understand it is (y2-y1) / (x2-x1). Example 1: (3-1) / (3-1) = 1 vs Example 2: (2400-1200) / (3-1) = 600
Caveat, I have looked at so many different websites trying to figure this out so if I am confusing radians for degrees or slope for linear regression etc than please excuse me.
I guess I’m just hoping that someone else came to my same conclusion and found a workaround for the y-axis issue and getting a slope result that can be used to determine a bullish or bearish bias using a set number, like 4 in my example on stocks with wide ranging prices.