If you read documents shared via the internet, chances are they will be either Microsoft Word (DOC) or PDF files. Given that these two ubiquitous file formats are often used (and misused), it’s not surprising many people get a little confused when trying to grasp how they differ and what the purpose of each is. And since the majority of PDF documents are created using Word, this can muddy the issue even further. This article outlines the basics of the two formats and (hopefully) gives less technical readers a better feel for what each format’s purpose is and how you should make use of them under different circumstances.

Basics of DOC and PDF files

Microsoft Word (DOC) files are composed in a proprietary format solely owned, maintained and updated by Microsoft. This means that Microsoft has complete control over how the format is developed in the future, and dictates how and by whom DOC files can be created.

The Portable Document Format (PDF) is an open specification created and maintained by Adobe Systems (originally), which recently became an ISO standard format. The openness, which expanded further by its formal standardization, means anyone can develop tools to edit and create PDF files. For long-term information storage, it means you can be confident that access to your documents is maintained. For long-term archiving, PDF’s openness makes it stand out.

Editing DOC and PDF files

One of the fundamental differences between PDF and DOC files and probably the least understood is file editability.

Microsoft Word (DOC) is a word-processing application, and its associated file format reflects this; it is readily editable, allowing you to add or change at will any text, images, tables or layout elements contained in the document. The tradeoff is that the file can look quite different on multiple computers and can be fairly easily edited by accident while viewing.

PDF editors and PDF. By contrast, PDF is a document delivery format based around displaying the contents very accurately, no matter what the platform.

What is not clear to a lot users of PDF files is why a PDF editor such as Nitro PDF Professional or Adobe Acrobat will not let you go in and quickly insert new paragraphs, rearrange table contents, and so forth. The reason most simply is that these are not word-processing applications — they are not designed for creating, composing and formatting documents from scratch.

When a DOC file is converted to a PDF file, all heading styles, paragraphs settings, and (most of the time) structure is discarded as this information is not needed to recreate a precise replica of the source document. When you look inside the contents of a PDF file, it simply describes how to layout a bunch of objects referred to in the PDF. So, in the PDF version, what looks like the same paragraph of text (with the exact same line spacing, indenting, etc.) as contained in the DOC file, is actually a whole bunch of small objects positioned precisely on the page.

An intelligent PDF editing application like Nitro Pro does a lot of smart stuff behind the scenes to make some sense out of all these objects on the page, helping to work out what objects form the words, what their properties are, and where lines start and end — it’s this intelligence that makes editing text and images in PDF files achieveable and useful. (This is also the reason why tools to convert PDF to Word are not as accurate as Word to PDF converters.)

The basic rule of thumb when working with DOC and PDF Files is, if you have a PDF file that requires very large text edits, such as replacing whole paragraphs or making major changes to the layout, then you should move back to the source DOC file. If you have smaller text correction tasks or need to edit images, then an application like Nitro Pro should be fine and save you some time, by removing the need to start the process all over again in Microsoft Word.

Content fidelity of DOC and PDF files

The flip-side of editability is content fidelity, which describes how faithfully the document received by the user reflects the one sent by the author. While the greater editability of Word documents is a better fit for document composition, its accordingly low content fidelity counts against it as a delivery format. For example, if a document contains an unfamiliar font, the recipient’s machine will not display the file correctly. In addition to their relatively low editability, appropriately prepared PDF documents contain all of the information (e.g. fonts) needed to faithfully display the file as the author intended. PDF documents are invaluable when content fidelity is key, such as document archiving, printing or in the heavily regulated legal or pharmaceutical industries.

Conclusion

PDF and DOC files each have their strengths, weaknesses and purposes, and it is not simply a matter of which format is “better”. PDF is the better ‘final format’ for maintaining the precise look of a file; Word is better for composing documents. When you put PDF and DOC side by side, the grayest area comes when document changes are required: do you return to the source file, or do you use a PDF editor to make the changes.