Choose file formats

The format in which research data are created usually depends on how researchers choose to collect and analyse data. This is often determined by discipline-specific standards and customs. Ensuring long-term usability of data requires consideration of the most appropriate file formats.

Available file formats

The safest option to guarantee long-term data access and usable data is to convert data to standard formats that most software are capable of interpreting, and that are suitable for data interchange and transformation.

It is important to choose platform and vendor-independent file formats where possible to ensure the best chance for future compatibility.

Danger of obsolescence

In principle all software is bound to become obsolete, however there are factors that should be considered in assessing a file format's long-term stability:

  • wide adoption
  • history of backward compatibility
  • good metadata support (in open format such as XML)
  • good range of functionality, but not overly complex
  • available interchange format with usable target
  • built-in error checking
  • reasonable upgrade cycle

Choose non-proprietary formats over proprietary ones

Popular formats such as those produced by Microsoft Office products (eg Word documents or Excel spreadsheets) are very likely to have reasonable longevity, but be aware that they are proprietary (owned by someone) and so will not necessarily exist forever or remain easily readable. We encourage researchers storing important information in open, non-proprietary formats – for example:

  • PDF/A rather than Microsoft Word
  • CSV  rather than Excel
  • TIFF rather than Photoshop files
  • XML rather than a database.

File format table

Here is a simple overview of some popular data formats and which to choose for long-term preservation. If you need more detailed advice please look at the UK Data Archive file format table.

Format GenreGreatAcceptableAvoid
TEXT .txt; .odt; .xml; .html .pdf; .rtf; .docx .doc
AUDIO .flac; .wav .ogg; .mp3, aif .wma; .ra; .ram; compression
VIDEO .mp2/.mp4, MKV   .wmv; .mov; .avi; compression
IMAGE .tif; .png; .svg; .jpg2000 .gif; .jpg .psd; compression
DATA .sql; .csv; .xml .xlsx .xls; proprietary DB formats
QUANTITATIVE TABULAR DATA .por .sav; .dta; mdb; accb  
GEOSPATIAL DATA ESRI Shapefile (essential - .shp, .shx, .dbf, optional - .prj, .sbx, .sbn); geo-referenced TIFF (.tif, .tfw); CAD data (.dwg) .mdb; .mif; .kml; .ai; .dxf; .svg