Mastering E-Prime: Meaning of all time audit measures.

Mon Feb 25 22:28:12 UTC 2013

Hello,

I really appreciate all the information.

After conducting a timing test, we find a consistent ~16 ms lag on the
EPRime/Screen presentation. It's possibly the result of the HDMI conversion
in the display monitor. Because the lag is completely consistent across all
trials, I assume that this is not particularly problematic with regard to
my EEG signals (for my purposes at least). However, we may try a VGA cable
to see if we can improve this delay in future.

In the meantime, I appreciate the information about the Task Events feature
and also the information about the EPrime programming course, which I am
going to look into.

Thanks! Justine

On Mon, Feb 25, 2013 at 4:07 PM, David McFarlane <mcfarla9 at msu.edu> wrote:

> As long as this thread has been reopened, I might as well mention that
> EP2.0.10.x adds more time auditing measures (including, e.g.,
> OnsetToOnsetTime!), so this report needs updating if it is to really
> include "all" time audit measures.  Don't know when I will get around to
> that myself.
>
>
> -----
> David McFarlane
> E-Prime training online:  http://psychology.msu.edu/**
> Workshops_Courses/eprime.aspx<http://psychology.msu.edu/Workshops_Courses/eprime.aspx>
> Twitter:  @EPrimeMaster (https://twitter.com/**EPrimeMaster<https://twitter.com/EPrimeMaster>
> )
>
>
>  On Friday, 10 September 2010 09:46:03 UTC-4, David McFarlane wrote:
>> When you look at the Logging tab on the properties page of any
>> stimulus object, you will find a host of items available for
>> logging.  Most of these are time audit data.  But what do all these
>> items mean, and what are they good for?  Chapter 3 of the E-Prime
>> User's Guide discusses time auditing to some degree, and the timing
>> diagram at Appendix E provides one way to see the relationships
>> between these items.  As an alternative, here I try to set out, in
>> order, a brief description of these items.
>>
>> First let us distinguish between timing control *settings* and time
>> audit *measures*.  The following items do not reflect any results
>> formed during the course of a stimulus but simply log the settings
>> provided by the user (e.g., you).  You may choose to have any of
>> these logged just to keep a record of settings active during the
>> experiment:
>> - Duration:  To reiterate, this does *not* show the actual duration of
>>    the stimulus, only the setting as provided by the user.
>> - PreRelease:  Affects the TargetOffsetTime (see below).
>> - TimingMode:   Event, Cumulative, or Custom, as set by the user (see
>>    the online E-Basic Help).
>> - CustomOffsetTime:  In Custom timing mode, overrides the
>>    TargetOnsetTime (see the online E-Basic Help).
>> - CustomOnsetTime:  In Custom timing mode, overrides the
>>    TargetOffsetTime (see the online E-Basic Help).
>>
>> Now, the raw time audit measures, listed in the order in which events
>> occur during the execution of a stimulus object.  These are all time
>> stamps in milliseconds from the start of the current program run:
>> - StartTime:  Time at which E-Prime started executing the stimulus
>>    object.
>> - TargetOnsetTime:  Scheduled time at which presentation of stimulus was
>>    to begin; set automatically from GetNextTargetOnsetTime (see online
>>    E-Basic Help).
>> - OnsetTime:  Time when E-Prime actually submitted the stimulus data for
>>    presentation (e.g., proceeded to copy data to display memory or load
>>    sound buffer).  This may not coincide with when the stimulus actually
>>    got presented, e.g., if data are submitted in the middle of a display
>>    refresh cycle then they may not get presented until the next refresh.
>> - ActionTime:  According to the online E-Basic Help, time at which
>>    E-Prime completed the "critical action" of the stimulus.  The
>>    documentation remains somewhat vague about this -- perhaps "critical
>>    action" means copying data to display memory, or loading a sound or
>>    video buffer.  In my tests, ActionTime never lags more than 1 ms
>>    behind OnsetTime, so it serves practically the same purpose as
>>    OnsetTime.
>> - TargetOffsetTime:  Scheduled time at which offset actions (e.g.,
>>    clean-up, ClearAfter, StopAfter) of stimulus object were to begin,
>>    e.g., OnsetTime + Duration - PreRelease (Event timing mode), or
>>    TargetOnsetTime + Duration - PreRelease (Cumulative timing mode).
>> - OffsetTime:  Time when E-Prime actually began the offset actions of
>>    the object.  Actions may not take practical effect until next
>>    vertical blank, or until presentation of next stimulus.
>> - FinishTime:  Time when E-Prime exited from execution of the
>>    stimulus object and proceeded to execute the next section of the
>>    program (e.g., next stimulus object or inline code).  Note that
>>    *execution* of a stimulus *object* may end before *presentation* of
>>    the *stimulus* ends; this is the point of PreRelease (as well as
>>    happening as a matter of course with some stimuli such as some
>>    sounds).
>>
>> Finally, a few composite time audit measures derived from the raw
>> measures above and provided for convenience:
>> - OnsetDelay = OnsetTime - TargetOnsetTime
>> - ActionDelay = ActionTime - OnsetTime
>> - OffsetDelay = OffsetTime - TargetOffsetTime
>> - DurationError = OffsetTime + PreRelease - OnsetTime - Duration
>>
>> Note:
>> - Time audit measures include the ActionTime that follows upon
>>    OnsetTime, but no corresponding item to follow upon OffsetTime.
>> - No time audit item for time stamp of vertical blank, although many
>>    stimuli do not take full effect until just after a vertical blank.
>>
>> -- David McFarlane, Professional Faultfinder
>>
>
> --
> You received this message because you are subscribed to the Google Groups
> "E-Prime" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to e-prime+unsubscribe@**googlegroups.com<e-prime%2Bunsubscribe at googlegroups.com>
> .
> To post to this group, send email to e-prime at googlegroups.com.
> For more options, visit https://groups.google.com/**groups/opt_out<https://groups.google.com/groups/opt_out>
> .
>
>
>

-- 
You received this message because you are subscribed to the Google Groups "E-Prime" group.
To unsubscribe from this group and stop receiving emails from it, send an email to e-prime+unsubscribe at googlegroups.com.
To post to this group, send email to e-prime at googlegroups.com.
For more options, visit https://groups.google.com/groups/opt_out.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://listserv.linguistlist.org/pipermail/eprime/attachments/20130225/b4992c67/attachment.htm>