EDAS II (Eye movement Data Analysis System II) provides three kinds of eye movement data analysis -

• Text. With text, EDAS II can be used for fixation sequence analysis and object-based analysis. The analysis of reading data yields a wide range of word-specific movement measures such as the size saccades to words, saccade duration, landing position, skipping rate, regression probability, number of passes through a word total number of fixations, and various fixation dependent measures (including first fixation duration, second fixation duration, gaze duration, total viewing duration, and more).
• Image. With images, EDAS II can be used to obtain a large number of oculomotor indexes for various to be analyzed regions. These oculomotor indexes include the size of the saccade to a region, the duration of the following fixation, the number of fixations within a region, cumulated viewing time for a region, the re-viewing of a region after other regions have been viewed, and more.
• iText - Image based text which is especially usefully for multiple language studies. Every experiment consists of multiple trials, each trail has multiple images and each image might have multiple line text.

EDAS II is well suited for the analysis of multiline data (Text/iText). With two dimensional recordings fixations often appear above or below a particular line as in Figure 2 below. EDAS II records but automatically corrects for intra-line deviations. EDAS II also corrects systematic vertical shifts as can be seen in Figure 3. Here line one and line 3 reading are accompanied by systematic upward-directed drift. Although the vertical difference between the first and last fixation on line two (fixation 15 and 25, respectively) is larger than the inter-line distance, fixation 25 is accurately assigned to line two rather than line one.

Features of EDAS II

"I've been using EDAS II for analyzing a large-scale reading Experiment: 30 subjects were each reading about 220 pages of text with each page containing up to 10 lines of text. The EDAS II program was immensely helpful when analyzing this data set. It has an algorithm that automatically assigns fixations to words and letters, and it also automatically corrects for many problems with drift or suboptimal calibration. The graphical display of eye movements on the stimulus material provides enormous help in getting a feeling for the data and allows for easy and convenient by-hand corrections that are necessary in such experiments (e.g., to mark bad trials, correct results from the algorithm, ...). Multiple aspects of the data can be displayed: e.g., fixated line number, fixation number, now also only a selected subset of fixations can be displayed. Very importantly, the developers of EDAS II have been VERY (!!!) helpful and constructive in working together to make EDAS II an even better Software for analyzing data from eye movement experiments. Not only did they provide extensive support with setting up the software and constructing the relevant files to get the analysis running. They were also highly responsive to include new features into the software when such features seemed useful to us from an applied perspective: e.g., manual responses can now easily be displayed with the eye movement data; also, only subsets of fixations can be displayed which can be a big help if many fixations lie in one area of the display; and many more and smaller changes were made in response to our suggestions. Lastly, EDAS II readily provides a large number of output variables, like gaze durations, single fixation durations, and many many more. Also here, the developers were very very helpful in defining new variables specifically for our purposes. Doing the data analysis for our dataset without EDAS II would have demanded a very high amount of programming work (e.g., in Matlab; in particular to deal with bad trials/fixations), but was quite convenient and feasible through the use of EDAS II. For this reason, and due to the good experiences that I've had with the software and the developer team, I advise to use EDAS II for analyzing data from eye movement experiments, in particular for multi-line reading experiments." - Daniel Schad, Ph.D candidate at Psychology Department, Posdam University, Germany

"I've used Entroware's EDAS II program for the analysis of eye movement data that we collected with different types of Eyelink systems. The program is perfect for my needs: it provides a graphical interface for the annotated viewing of raw data, it allows me to select -per mouseclick- trial data that are to be accepted, to be edited, or to be rejected, it allows me to import experimental condition files into to be analyzed data sets, and it yields two excel-type outputs: one in which fixation order determines the ordering of output data and one in which the order of words in the text determines the ordering of output data. The word-order spreadsheet includes a large number of conventional indexes that are frequently used in the study of reading (such as incoming saccade properties, first fixation duration, gaze duration, total viewing duration, skipping, outgoing saccade properties) and some that are rarely used (e.g., pupil size during word viewing, intrafixation movement dynamics). Best of all, EDAS II has been modified in response to user-specific demands, giving it the feel of a custom-tailed program. For my purposes, it's a great research tool with superb support." - Albrecht Inhoff, Professor at Psychology Department, SUNY/Binghamton, United States