Describe adjudication as an administrative action.

Essentially, the Administrative Procedure Act (APA) grants agencies the ability to create orders, which allow for the final settling of a matter.  The administrative action would be the process by which the agency adjudicates (makes an order, judgment, or decree) an issue.  While the actual process may differ from agency to agency, one reason the APA was created was to ensure all procedures comply with the constitutionally protected right of Due Process.  The process must include the right of the affected to a hearing (either under Due Process or expressly stated in a statute), and is usually completed with some form of written report.  
The Administrative Procedure Act (5 U.S.C. Subchapter II) defines adjudication as "agency process for the formulation of an order." (Sec. 551, 7)
An agency is defined as "each authority of the Government of the United States, whether or not it is within or subject to review by another agency, but does not include the Congress; the courts of the United States; the governments of the territories or possessions of the United States; the government of the District of Columbia; or except as to the requirements of section 552 of the the APA, agencies composed of representatives of the parties or of representatives of organizations of the parties to the disputes determined by them; courts martial and military commissions; military authority exercised in the field in time of war or occupied territory; or functions conferred by [various sections]. (Sec. 551, 1)
Agency action "includes the whole or part of an agency rule, order, license, sanction, relief, or the equivalent or denial thereof, or failure to act;" (Sec. 551, 13)
An order is defined as "the whole or part of a final disposition, whether affirmative, negative, injunctive, or declaratory in form, of an agency in a matter other than rule making but including licensing." (Sec. 551, 6)
 
 

Adjudication is an administrative action because it takes place outside of the courtroom’s normal judicial procedures and because it seeks to find a compromise or settlement in a dispute rather than find guilt or innocence. Its functions can involve a judge, as with a trial, or a professional adjudicator who specializes in helping parties arrive at a settlement. Adjudication is similar to a trial in that rules of evidence apply and decisions are binding, although enforcement mechanisms can be protracted and problematic for the party in whose favor the judge or adjudicator has ruled.
To reiterate, the defining characteristic of adjudication is that it seeks to resolve a dispute for which a more formal judicial process is not necessary. The decision of the presiding judge or adjudicator is legally binding, but enforcement mechanisms are less expeditious than is the case in a formal trial. Arbitrated or adjudicated processes are also considerably less expensive than formal trials, so they are preferred when the risks of incurring court costs as part of a decision or settlement are considered.