TEDS Data Dictionary

Raw Data files

These are currently stored in the \System\Rawdata\18yr\ folder, and the list below refers to files and sub-directories within this folder.

The Access database has been periodically updated to keep it in the most recent Access format, to avoid software compatibility issues. Nevertheless, the essential data from the tables are also stored in exported "copies" in the form of the csv files in the Export folder.

• 18yr.accdb.
  This is the Access database file (2007 format) containing aggregated and cleaned 18 Year raw data from the questionnaires and from administrative sources. This database file also provided the programs for manual data entry of the questionnaires.
  This Access database is now the master copy of the data, and is the source of such data for the analysis dataset. The main data table in the database is called TwinQnr - data entered from the twin questionnaire. Admin data relating to the 18 year study are held in two tables: yr18Progress (for the questionnaire study) and TwinContactProgress (for the twin contact study). There are several other reference tables, containing lists of subjects, qualification types, etc. The contents of these tables are used to add value codes to appropriate variables in the analysis dataset.
• \Export\ subdirectory, containing exported 18 Year raw data files. These files are directly used to construct the analysis dataset.
  The csv files are exported from the Access database described above. The Perception, FFMP, Bricks, Kings Challenge and Navigation web study data files are SPSS data files containing raw data aggregated for each study respectively. The files are called:
  • TwinQnr.csv (twin questionnaire data)
  • 18yAdmin.csv (admin data from table yr18QnrProgress, including questionnaire return dates)
• \web data files\ subdirectory, containing containing aggregated web test data files. There is one file for each of the twin web studies. In each file, identifying fields (like names) have been removed. These files were aggregated, with some cleaning, from the raw analysis files that were originally downloaded from the web server. The web data files are as follows.
  • 18yr_fashion.csv (twin FFMP web study data)
  • 18yr_bricks.csv (twin bricks web study data)
  • 18yr_kings_challenge.csv (twin kings challenge web study data)
  • 18yr_navigation.csv (twin navigation web study data)
  • 18yr_perception.csv (twin perception web study data)
  • 18yr_perception_retest.csv (twin perception web re-test study data)

Dataset files

These files are currently stored in the \System\Datasets\18yr\ folder. The following list refers to items within this folder.

• Rdb9456_full.sav - the SPSS version of the full 18 Year dataset, including every variable
• Rdb9456_reduced.sav - a reduced-size SPSS version of the 18 Year dataset, with all web test item variables removed
• \working files\ - this subdirectory contains various intermediate files, saved during the process of converting the raw data into the dataset. These files include working datasets r1merge, r2clean, r3derive, r4label, r5double (all .sav files), saved at the end of the 5 scripts. The latter file is identical (except for the name) to the final dataset Rdb9456_full.sav.

Syntax files (scripts)

These files are currently stored in the \System\Scripts\18yr\ folder.
Note that these are SPSS syntax files. The names of the scripts are R1_merge, R2_clean, R3_derive, R4_label, R5_double (all .sps files). The processing carried out by these scripts is described on another page.