Ethics are the moral principles that govern a person's behavior. Within the realm of parliament, there are expectations placed on MPs, as representatives of the people, that they will abide by a set of ethics in the manner in which they conduct their work.

Even though there are international norms, every country will have its own definition of what is ethical and the parliament will need to define ethical behavior for its members. This starts with a code of ethics (sometimes a series of rules) in which the MPs are expected to meet the rules laid out in the code. The code will be an important statement by the parliament as to what is proper behavior and to instill a culture of honesty and transparency. Such a code should recognise several objectives, including: 

• The need to maintain the public's trust in the work of the parliament
• To avoid any misunderstanding and to guide MPs in managing their personal interests and those of their public life
• Ensuring the public is confident that their politicians are meeting a reasonable standard of care in conducting their work
• To provide a system by which the public is made aware of the activities of MPs as it relates to meeting minimum standards
• Provision of an independent system to resolve any disputes as to the ethical behavior of an MP

Of particular interest is the need to manage and define conflicts of interest. The OECD defines a conflict of interest as:

A conflict of interest involves a conflict between the public duty and private interests of a public official, in which the public official has private-capacity interests which could improperly influence the performance of their official duties and responsibilites. [OECD Guidelines for Managing Conflict of Interest in the Public Service]

MPs must always ensure that their personal interests are not influencing their public duties. The most common way in which this occurs in where a MPs are required to recuse themselves from a vote on a draft law in which the result of the vote would directly affect a personal or familial interest, be it financial or otherwise.

A second key area of ethics is in the receiving of gifts or donations. Many parliaments place a limit on the value of gifts that can be received by an MP while in office. Others require that all gifts be reported. 

This leads to another critical point with regard to ethics. The system works where the MPs are required to report regularly (usually on an annual basis) about their financial dealings, any gifts received and other changes in their personal and familial interests that may be reflected in their work as an MP.

No matter the content of a code of ethics, there are three common means by which such codes are enforced. First, given parliaments critical need to maintain independence, many of the codes are self-regulated with the parliament having a disciplinary committee that will conduct investigations and determine punishment, if any. An alternative system is to have a quasi-judicial or judicial body that can investigate and prosecute violations of the code of ethics. Finally, a hybrid system is to have an independent ethics commissioner that reports to parliament but has the resources and authority to investigate and punish ethical violations.

Every parliament, if it is to maintain the confidence of the public, must establish a minimum standard of ethical behaviour. The use of a code of ethics and mechanism for investigation and discipline is critical to ensure the public is confident its MPs are working in the public interest.