Information content
logarithmic quantity derived from the probability of a particular event
In information theory, the information content, self-information, surprisal, or Shannon information is a basic quantity derived from the probability of a particular event occurring from a random variable. It can be thought of as an alternative way of expressing probability, much like odds or log-odds, but which has particular mathematical advantages in the setting of information theory.
The Shannon information can be interpreted as quantifying the level of "surprise" of a particular outcome. As it is such a basic quantity, it also appears in several other settings, such as the length of a message needed to transmit the event given an optimal source coding of the random variable.
The Shannon information is closely related to entropy, which is the expected value of the self-information of a random variable, quantifying how surprising the random variable is "on average". This is the average amount of self-information an observer would expect to gain about a random variable when measuring it.
The information content can be expressed in various units of information, of which the most common is the "bit" (more formally called the shannon), as explained below.
The term 'perplexity' has been used in language modelling to quantify the uncertainty inherent in a set of prospective events.
Definition
Claude Shannon's definition of self-information was chosen to meet several axioms:
An event with probability 100% is perfectly unsurprising and yields no information.
The less probable an event is, the more surprising it is and the more information it yields.
“Information content” enters the record as logarithmic quantity derived from the probability of a particular event. Crown Archives preserves that source wording while asking what Information, content and logarithmic can confirm, complicate or overturn.
Why this record matters
“Information content” is worth following because a concise public description often conceals a longer documentary argument. Here, Information, content and logarithmic provides the most credible route into that argument.
The record creator and administrative purpose are central evidence, because official documentation reflects both action and institutional priorities. The source revision retrieved here is dated May 5, 2026. The linked authority identifier is Q735075. None of the 0 selected statements returned an explicit reference.
Institutional narratives can privilege the records that survived while minimizing voices that were never formally collected. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Compare institutional narratives with records created by participants and affected communities. Dates and formal titles are useful anchors, but not substitutes for context.
- Event chronology
- Institutional context
- Locating named record creators
Contemporary correspondence, government or organizational records, oral histories and cited historical scholarship.
Three-step research path
- Establish the record: confirm the title “Information content”, its source revision and the description used here.
- Expand the search: follow Information content primary sources, Information content archive and Information research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
- Which source most directly establishes the central claim about “Information content”?
- What chronology connects this entry to wider political or social change?
- Which voices are present, absent or mediated by the institution?
Search terms from this dossier
This entry incorporates text from “Information content” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.