Download software Tutorial videos
Subscription & data-feed pricing Class schedule


New account application Trading resources
Margin rates Stock & option commissions

Attention: Discussion forums are read-only for extended maintenance until further notice.
Welcome Guest, please sign in to participate in a discussion. Search | Active Topics |

Relative Strength Indicator Rate this Topic:
Previous Topic · Next Topic Watch this topic · Print this topic ·
hfowler
Posted : Wednesday, March 11, 2009 12:00:33 AM
Registered User
Joined: 3/21/2005
Posts: 7
In Achelis' Technical Analysis from A to Z, he gives the formula for calculating the RSI. After using this method, I came up with different numbers from what you have. My question is: What is your method of calculating the RSI?
Thank you for your help, again.
Craig_S
Posted : Wednesday, March 11, 2009 6:33:34 AM


Worden Trainer

Joined: 10/1/2004
Posts: 18,819
Are you talking about Relative Strength or Wilder's Relative Strength Index (RSI)?


- Craig
Here to Help!
hfowler
Posted : Wednesday, March 11, 2009 12:56:02 PM
Registered User
Joined: 3/21/2005
Posts: 7

I'm referring to Wilder's Relative Strength. In the Technical Analysis A to Z book, they give the basic formula. When I calculate the formula, the results do not match yours no matter what period I use, e.g. the standard 14 day or shorter one, 9 day. Evidently, I've missed a step so that's why I asked what method you use for your calculations. The more specific, the better.

Bruce_L
Posted : Wednesday, March 11, 2009 1:13:54 PM


Worden Trainer

Joined: 10/7/2004
Posts: 65,138
hfowler,
The basic formula for Wilder's RSI as given in most sources is:

100 - (100 / (1 + (U / D)))

A less obscure way to write this would be:

100 * U / (U + D)

Where:

U is a Moving Average of Upward Price Changes.
D is a Moving Average of Downward Price Changes.

TeleChart has two ways to calculate this base Wilder's RSI.

The first way is when Use Wilders Smoothing is checked and will agree with most other technical analysis software (and with the A-Z Companion Spreadsheet). In this instance, the Moving Average used to calculate U and D is a Wilder's Smoothing of the same Period as the RSI. Wilder's Smoothing is a type of Exponential Moving Average where the Period is different. You can multiply the Wilder's Period by two and then subtract one to get the equivalent Exponential Moving Average Period.

The second way is when Use Wilders Smoothing is not checked. When this is the case, the Moving Average used to calculate U and D is a Simple Moving Average of the same Period as the RSI.

TeleChart's RSI has additional Avg Period and Average Type settings that are not part of most RSIs. These simply add either a Simple or Exponential Moving Average with a Period equal to the Avg Period to the RSI as calculated above. If the Avg Period is set to 1, the RSI will act as if these settings are not there.

-Bruce
Personal Criteria Formulas
TC2000 Support Articles
bustermu
Posted : Thursday, March 12, 2009 8:06:01 AM
Registered User
Joined: 1/1/2005
Posts: 2,645
hfowler,

I am guessing but the reason for the disagreement may be your interpretation of:

U - An average of upward price changes.
D - An average of downward price changes.
 
In calculating U, replace the the price change by zero if it is not an upward price change.
In calculating D, replace the the price change by zero if it is not an downwardward price change and change the sign of the downward price changes.

For example, if the price changes are:

+1, +2, +1, 0, -1, -2,

then, for simple moving averages,

U = 4/6
D = 3/6

The values

U = 4/3
D = 3/2

are not intended.

Thanks,
Jim Murphy
Users browsing this topic
Guest-1

Forum Jump
You cannot post new topics in this forum.
You cannot reply to topics in this forum.
You cannot delete your posts in this forum.
You cannot edit your posts in this forum.
You cannot create polls in this forum.
You cannot vote in polls in this forum.