The Experiment Log Request Form allows you to
retrieve the log in "raw" form, allowing independent analysis
of the raw experimental data as captured. The log file is an
ASCII comma-separated-value (CSV) file; many spreadsheet
programs can import this format, facilitating analysis without
the need to write special-purpose programs.
The following table describes the contents of the individual fields
in each log record. If the first character of a field is a single
quote (') or double quote (") character, the field is a quoted
string terminating with a like quote character, with any of the special
characters ', ", and \ escaped by a backslash (\).
Field
| Description
|
1 | Log format
|
2 | 1 = Live data, 0 = Internal debug (ignore)
|
3 | Experiment name
|
4 | Mode (Practice/Record)
|
5 | Goal
|
6 | Sound enabled?
|
7 | Subject identity
|
8 | Subject's IP address (suppressed)
|
9 | Subject's host name (suppressed)
|
10 | Time and date of run (Unix time() format)
|
11 | Random data for run
|
The contents of the fields is as follows:
- Field 1: Log format
- To permit future extensions of the log file format, each record
begins with an integer format indicator. The current log file format
is
1
; programs written to process this format should
ignore any records with a greater format indicator.
- Field 2: Live data?
- To allow extensive "all-up" testing of the various experiments
without overloading the hardware random number generator,
the experiment generator can be configured to deliver software-generated
pseudorandom data for test purposes. Debug runs with pseudorandom data
are flagged by a zero in this field. Only runs with actual random
bits, indicated by a one in the field, should be used for statistical
analysis.
- Field 3: Experiment name
- This field specifies the internal name of the visual feedback
program selected by the user for this run.
- Field 4: Mode
- This field will contain "Record" or "Practice" depending on the
mode selected by the user. Practice runs are usually excluded from
statistical analysis, but can be returned by checking the
corresponding box in the Log Report Request Form.
- Field 5: Goal
- The goal selected by the user for the run. The field consists
of a one or zero indicating which bit the user was attempting to
cause to occur most often, followed by a comma and a text description
of the corresponding result in the visual feedback program. For example,
in the Clock Face feedback program, one bits cause the clock to
advance in a clockwise fashion while zero bits set it back in the
counterclockwise direction. Selecting the clockwise goal in the
Clock Face experiment results in a Goal field in the log
of "1:Clockwise".
- Field 6: Sound enabled?
- Each of the feedback programs provides a form of optional audio
feedback. If chosen by the user, this field will be "-s", otherwise
"-n". The low-level option passed to the generating program is
recorded in the log to permit representation of more complex
audio feedback requests in the future.
- Field 7: Subject identity
- When making Record runs, users are required to specify a user
identity which is normally their E-mail address but may be, if the
user is concerned with disclosing this information, an arbitrary
string allowing separate runs by that user to be grouped together.
The actual identity string entered by the user is recorded in
the log file, but cannot be retrieved across the Internet. Instead,
individual subjects are assigned "
Subject_
n"
numbers. If you've entered your own user identity when requesting
the log report, your own runs will contain "Me" in this field.
- Field 8: Subject's IP address
- In the master log, this field records the Internet address of the host
from which the experiment was requested. For privacy reasons, it is not
disclosed in log reports.
- Field 9: Subject's host name
- In the master log, this field records the host name, if available,
from which the experiment was requested. For privacy reasons, it is not
disclosed in log reports.
- Field 10: Time and date
- Time and date when the experiment was run, expressed in the
Unix
time()
convention of the number of non-leap
seconds since 1st January 1970, Universal (Greenwich Mean) Time.
C and Perl programmers can convert this number to a conventional
date and time with the gmtime()
function. Users of
Excel on Microsoft Windows can
convert a Unix date d into an Excel "serial number" with the
formula =((
d/86400.0)+25569)
.
Macintosh users of Excel must, of course, to satisfy the rapacious
appetite of Gates, Prince of Incompatibility, use a different formula
which, not owing a Macintosh, I can't provide you here.
- Field 11: Random data stream
- Finally, this field contains the actual data stream from the
hardware random number generator used for this run. The bit stream
is expressed as a hexadecimal number, 4 bits per character, using
the character set
0123456789ABCDEF
.
What, no analysis?
Right! If you request raw data, and that's precisely what you
get--just the description of the experiment requested by the user
and the random number stream delivered to the feedback program.
Log reports which include statistical analysis are available; raw
data is for those who don't trust our analysis and wish to
verify it for themselves (and thank you for doing so!), and
folks who want to conduct other studies based on the experiment
database collected here.
by John Walker
kelvin@fourmilab.ch