What is a TICK?

Ok phy - I'll bite :)

IMHO - its 'an alteration in offered Bid &/or Ask price of a particular security on a particular data feed'

Usually moving the opposite way to what you'd like :(

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I dont subscribe to the common link with 'ticks' to a minimum size of movement & the confusion between pips & ticks

-BB-

Here is one more definition of tick:

What causes the Server to emit a "tick" ?

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Test results:

Change in Bid, or Ask, or both, gives a "tick".

Occasionally, there will be a tick recevied with no change in Bid or Ask. What does this tick have to say?

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There are many datafeeds of qoutes exist. What is nature of each tick in them?

For this discussion, I only want to understand the MetaTrader tick.

Test script...

//+------------------------------------------------------------------+
//| script program start function                                    |
//+------------------------------------------------------------------+
int start()
  {
    double oldBid, oldAsk, oldVolume;
    int oldTime;

   oldBid = Bid;
   oldAsk = Ask;
   oldVolume = Volume[0];
   oldTime = Time[0];
   
   int bidChange, askChange, eitherChange, neitherChange, bothChange, tickCount;

    while(!IsStopped()){

       RefreshRates();
       if(oldVolume != Volume[0]) tickCount += 1;
       if(oldBid != Bid && oldAsk == Ask) bidChange += 1;
       if(oldAsk != Ask && oldBid == Bid) askChange += 1;   
       if(oldBid != Bid && oldAsk != Ask) bothChange += 1;
       if(oldBid == Bid && oldAsk == Ask && oldVolume != Volume[0]) neitherChange += 1;
       
       Comment("\n"+
                   " Bid Change       = " + bidChange + "\n" +
                   " Ask Change      = " + askChange + "\n" +
                   " Both Change     = " + bothChange + "\n" +
                   " Neither Change = " + neitherChange + "\n" +
                   " Sum of above   = " + (bidChange + askChange + bothChange + neitherChange) + "\n" +
                   " Tick Volume      = " + tickCount);
                   
       Sleep(16);
                   
        oldVolume = Volume[0];
        oldBid = Bid;
        oldAsk = Ask;
        
    
    }


   return(0);
  }

Hi

Very, very interesting question!!

I go back to old equity days and you could only short on a down tick. Which leads me to believe that each tick represents a closed trade.

Thus a trade might close on different bid or ask. but could also close on exactly the same bid and ask which would generate a tick without a change.

The three no change ticks in your sample would be of this nature.

Only MHO, would really like to get authoritative answer.

Keith

if I think well :

Have I the right?

Ok... summary:

BarrowBoy - a change in bid and/or ask

Rosh - a "new price" event

kminler - each tick represents a closed trade

puncher - a tick is a pip

.

Test shows that when a new bid or ask occurs a "chart tick" comes along with it. The script watches Bid, Ask, and Volume repeatedly, it is not "driven" by ticks. Every price change in Bid or ask is accompanied by a change in Volume, whcih has previously been proven to be equivalent to the number of times that the start() function is called for an indicator or EA.

.

Test shows occasionally there is a "tick" without a Bid/Ask price change. Has something else changed that I am not monitoring that provokes the tick to be emitted? I'll expand the test.

.

If ticks are closed trades, then I would expect to see EURUSD be the fastest "ticker". It is not.

.

Script enhancement, to monitor changes in MarketInfo...

.

I have found that a "tick" is received with no Bid/Ask change on the tested pair when there is a change in the MarketInfo TICKVALUE, and also change in MARGINREQUIRED. So, a change in another currency pair can cause a tick to occur on the Pair Under Test. Ticks come with changes to MarketInfo() values.

.

So... New definition for MT4 tick is:

A tick is a notification from the Dealer about a change in current dealing prices or trading conditions/parameters.

.

And that raises the question, why some of these changes would be used to drive chart bars and chart "volume"...

Phy

This is fascinating stuff :)

>"...I have found that a "tick" is received with no Bid/Ask change on the tested pair..."

Does this imply a change in price at a scale beyond the number of decimal points MT supports?

Or...

Does this only apply to synthetic crosses & is the result of coincident changes in the base pairs that cancel out for the cross?

-BB-

New price (differenced from previous) => new tick. No other explanation.