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Convention versus Best Practice versus Standard

Definitions

Convention — an agreement, implicit or explicit, among a group. My practice is mine alone, but if all or most of us do it that way (good or bad), it's a convention, a "coming together" in agreement on this one practice.

Best Practice — specifies what we ought to do without regard to whether we do it.

Standard — what we have agreed we will in fact do, to some specified level of detail.

Examples

Convention

By convention street signs in the U.S. are placed at street corners, we expect to find them by looking up, not down, and we expect them to be horizontal, not vertical. The benefits of this convention are:

• We can locate street signs quickly, with a minimum of effort
• Their appearance makes it easy to distinguish them from everything else

By convention books have a table of contents that occur somewhere in the first few pages, page numbers are somewhere in the margins and they will look like a table of contents and page numbers.

By convention XML tags are indented to reveal their nesting structure.

Best Practice

It is best practice when creating XHTML documents to wrap all abbreviations within an <abbr> element, e.g.

    <abbr title="Extensible Markup Language">XML</abbr>

The benefit of this best practice is this: people with visual disabilities use a screen reader to read Web pages. Screen readers often mispronounce abbreviations. By providing the full text version of an abbreviation, a screen reader tool can better assist the user.

Standard

The XML specification is a standard. It requires, for example, every XML document to have a root element.

Another example of a standard is the meter.

Characteristics

Convention

• Oftentimes a convention is localized. In the U.S. the convention is to put street signs on street corners. In the U.K. the convention is to put street signs along the road.
• Conventions evolve over time. In the print industry the convention of what goes into a Table of Contents and where the TOC should appear have changed over time.
• Conventions oftentimes become part of the background and we don't think about or notice them. We only notice them when they are not followed. For example, when an XML document is not indented we become acutely aware of the indentation convention.

Best Practice

• Informal adoption.
• Explicit documentation.

Standard

• Formal adoption.
• Authority.
• Formalized agreement.
• Explicit documentation.

Reduces Cognitive Load

Conventions and standards help reduce cognitive load.

The convention of putting the main header of a story in big, bold font and subheaders in smaller font instantly gives the reader some understanding of the general organization of a document. The user doesn't have to spend the mental effort to figure out the organization and main points.

The XML standard gives us a syntax for formatting data — wrap data within tags. Thus, the standard enables us to focus on the data rather than spending the mental effort of devising a data format syntax.

Last Updated: July 23, 2008

Note: The street sign and book Table of Contents examples come from the book Don't Make Me Think by Steve Krug.