User`s guide

E-Prime User’s Guide
Chapter 2: Using E-Studio
Page 68
2.13 Stage 11: Research Program
Development
Note, some users may include copyright notices in their experiments. Be respectful of the
constraints authors place on sharing script, and always give credit for script used.
2.13.1 Modifying experiments
When modifying experiments, it is important to maintain consistency as much as possible. This
will aid not only in the understanding of the differences between versions of an experiment, but
also in the merging of data files collected by different versions. Consistency should be
maintained not only in the naming of the experiments themselves, but also in the naming of
factors and attributes within the experiments. For example, it would be easiest to view the
differences between files if objects performing similar duties were similarly named (e.g., the
object presenting the stimulus should be consistently named Stimulus). Procedures running
tasks at specific levels of the experiment are more easily understood if named to reflect the level
(e.g., TrialProc, BlockProc).
When making modifications to an existing experiment, it is recommended that new conditions be
added rather than deleting old conditions, making the new experiment a superset of the modified
experiment. Detailed records should be kept to outline the differences between versions of an
experiment (refer to section 2.12.1 – What files to store). Another useful practice is to name
versions of the same experiment using a consistent experiment name and a version number
(e.g., ExpName-001.es).
With the intention of merging data files, care should be taken to maintain consistency in the
naming of variables (i.e., attributes and levels). For example, if an attribute is named “Stimulus”
in the first version of an experiment, and “Stim” in the second version, the merging of the data
files obtained by the two versions would result in two columns of data for what is essentially a
single attribute. The values for half of each column would be set to NULL. The user would
necessarily have to copy and paste information in order to relocate the appropriate information.
Consistency in naming of levels and attributes will avoid potential errors during the merging of
data files. E-Merge will report problems if the same name is used to refer to an attribute in one
data file and a level in another. Likewise, errors will be generated during a merge operation if a
single name is used to refer to different levels in different data files (e.g., level 2 is called “Trial” in
al” in another). With the exception of the same name being used for
both a variable and a level, the problems are not impossible to overcome, but are inconvenient
and would require some manual editing. Refer to the Chapter 5 – Data Handling in the User’s
Guide for more detailed information concerning conflicts during merge operations.
Take care not to change the meaning of a variable across experiments that are to be combined
for analysis (e.g., Do not use Probe to refer to animals in one experiment, and fruits in another).
If need be, add a new attribute or level, but avoid changing the experiment without modifying the
logged variables.
2.13.2 Sending experiments to colleagues
An E-Prime license owner is free to distribute any files created by using the system. Files created
by users include Experiment Specification files (ES), E-Basic Script files (EBS), data files (EDAT,
EMRG), and analysis files (ANL). However, according to the license agreement, users are not
permitted to distribute any part of the E-Prime system, including the run-time application. Refer to