This is a guide how to use the data portal DDI on Rails, which builds the foundation for the new version of SOEPinfo.
DDI on Rails is created in order to assist the user to explore survey data (e.g. the SOEP), to compile personalized datasets and to publish the results on the publication database. Primarily, it guides the user throughout the entire process of their research projects using the SOEP data from conception to publication and citation.
On the main page a search option can be found, providing a quick way to be navigated directly to the respective results if the user has a specific variable, dataset, or topic in mind. It also helps for a quick overview if the user's interest is to find out if there is any data available for his/her research topic/question.
For instance, if you are looking for at the results for the keyword "age", you can find a total of 2614 items listed. However, this might be overwhelming. Thus, it provides you a way to narrow your search output, using so-called facets. Possible classes above the total results are "Concepts", "Variables", "Questions" and "Publications" - each of them with optimized facets for the particular class.
The select box for studies is the only one, available in all views. This makes it easy for the data users of one particular study to consistently adjust all result views. The descriptions to those studies can be found on the very top of the page under "Studies" after a particular study is selected and will be specified in the next section again.
The already mentioned classes with its assigned symbols are listed again underneath the "Study" option and below that another sorting option regarding the analysis unit can be selected.
DDI on Rails incorporates various SOEP-studies, including "SOEP Core study", "SOEPlong", "Families in Germany", "SOEP Innovation Sample", "SOEP Pretest", "Base II", and "SOEP Test Study". A particular study can be accessed as shown in the picture below. After a study of interest is selected, a general overview will be displayed. Moreover, the total number of involved variables and datasets can be viewed.
In the variable browser, there is another search engine adapted to the chosen study. That way you can find your required variables in the particular study. The same holds for the dataset browser. Furthermore, the variables can be selected according to the desired analysis unit or period on the left-hand side.
A variety of topics can be selected on the very top of every page next to "Studies". After clicking on a particular topic, several subtopics appear. The user may also use the search engine to look for specific concepts regarding the chosen topic.
Concepts are used to group variables within one study or in between multiple studies, that might have slight variation but still put themselves forward to be analysed in a comparative way. They replace the so-called "item correspondence" from the former SOEPinfo.
Under "publications" you can search for any keyword and you will be directed to a list of papers that involve the searched word(s). Each result provides a link to the publication for direct access.
While the former SOEPinfo allowed the use of the basket and its script generator without any login information, the new system requires you to log in in order to create baskets for variables.
The login is necessary to enable some of the new features in DDI on Rails, among others the possibility to store multiple baskets at a time and access those baskets directly from most statistical packages.
After having signed in, a new basket-symbol appears on the very top. Now you can create new baskets and fill in the individual information for each basket. To enable comparison between studies and distributions (versions of one study) later in the process, it is necessary to bind the basket to a particular distribution.
All variables of interest accessed as previously explained can be selected into your basket now by clicking on the green "Add to basket" symbol underneath the variable in the variable browser. The number next to the basket indicates how many variables are already integrated into your basket.