This is the second in our new series of Good Decision-Making Guides for Public Bodies. These Guides highlight what is best practice in decision-making and offer simple and practical tips to reduce the risk of challenge to your decisions.


There are three fundamental principles of good decision-making that decision-makers in public bodies must always have in mind when making decisions.

The decision-making body must:

i. have the legal power to make the decision.

ii. have regard to any relevant factors and exclude any irrelevant considerations.

iii. make a rational decision.

In this Guide we look at each of these principles.


The decision-making body must have the legal power to make the decision. If it does not, it will be acting beyond its powers (or ultra vires) and the decision will be invalid.

The power to make a decision may be:

  • Express: set out in primary legislation (statutes) or secondary legislation (orders, rules, regulations, bye-laws).

    For example, the Central Bank (Supervision and Enforcement) Act 2013 gives the Central Bank an express power to "give a direction in writing to [a] regulated financial service provider... to take [specified] actions."
  • Implied: a power will generally only be implied where (i) it is justified by the statutory context; (ii) it is not of such a nature that you would expect to see it set out specifically; and (iii) it is consistent with the statutory scheme (see example below).
  • Incidental: a power to do whatever is incidental to or consequential upon specific statutory powers. The extent of these powers will depend on the general policy underlying the legislation in question.

    For example, the Personal Injuries Board Assessment Act 2003 gives the Injuries Board "all such powers as are necessary or expedient for, or incidental to, the performance of its functions under this Act."


The Commission to Inquire into Child Abuse sought to limit the number of legal representatives who could be present during evidential hearings to one solicitor and one barrister per party. It did not have an express power to do this under the Commission to Inquire into Child Abuse Act 2000.

The Commission argued that the power was implied and incidental to the obligation imposed on it under the Act to conduct evidential hearings "in an atmosphere that is as sympathetic to, and as understanding of, [victims] as is compatible with the rights of others".

High Court: A power to limit legal representation could not be implied. If the Commission were to be given such an unusual and far-reaching power, express legislative authority would be required (Re Commission to Inquire into Child Abuse).

The power to make a decision must be exercised properly. In some cases, the purposes for which a power may be exercised will be set out in the relevant legislation. Where the purpose of the power is not set out explicitly, it must be determined by implication from the subject-matter, scope and purpose of the legislation as a whole.


The Solicitor Accounts Regulations give the Law Society power to appoint an accountant to investigate whether a solicitor has complied with the Regulations.

The Law Society appointed an accountant under the Regulations and instructed her to (i) ascertain whether the solicitor in question had complied with the Regulations; and (ii) look for evidence of fraudulent personal injuries claims. On the basis of the accountant's report, the Law Society decided to seek a disciplinary inquiry into the solicitor.

Supreme Court: In instructing the accountant to investigate alleged fraudulent claims, the Law Society tried to pursue a purpose which was not authorised by the Regulations. The decision to appoint the accountant was invalid and the report was inadmissible (Kennedy v Law Society of Ireland (No 3)).


The decision-maker must have regard to all relevant factors which are before it and must disregard any irrelevant factors.

Relevant factors: In some cases, legislation will set out the factors which the decision-making body should or must take into account. Always check whether the list of factors is intended to be exhaustive. Look out for words such as "in particular" or "including" (e.g. the decision-making body shall have regard "in particular to..."). This suggests that the factors listed are not exhaustive and there may be other relevant factors arising from the circumstances of the case.

It is important to identify which factors are mandatory (i.e. must be taken into account), and which factors are discretionary (i.e. can be taken into account).

Irrelevant factors: Taking account of an irrelevant consideration may also provide grounds for judicial review.


A doctor applied for a position with the Southern Health Board. He was told that extra credit would be given to applicants who passed an optional Irish language test. He did not sit the test and was not offered the position. He later learned that the test had proved crucial in the selection of the successful candidate. He challenged the decision of the Board on the basis that the sole power to declare the appropriate qualifications for the position rested with the Minister for Health and competence in oral Irish was not a qualification prescribed by the Minister.

Supreme Court: The Board had acted outside its powers in introducing a new and unauthorised qualification (The State (Cussen) v Brennan).

Decision-making bodies may sometimes be required to "have regard to" a particular opinion, report, guideline, recommendation etc. This requires the decision-making body to give reasonable consideration to the particular matter, but not to follow it without question.


The mother of a child with autism applied to the Department of Social Protection for domiciliary care allowance.

Under the Social Welfare Consolidation Act 2005, applications for domiciliary care allowance are determined by a 'deciding officer' in the Department, who must "have regard to" the opinion of a Department medical assessor.

The deciding officer refused the application on the basis of the opinion of the medical assessor. The mother challenged this refusal, claiming that the application was decided by the medical assessor and not by the deciding officer. The deciding officer in question had dealt with 3,806 applications and had followed the opinion of the medical assessor each time.

High Court: The deference shown by the deciding officer to the opinion of the medical assessor was so great that in reality it was the medical assessor who determined the application. This breached the provisions of the Act and tainted the decision-making process (B v The Minister for Social Protection).


Your decision must be reasonable. This does not mean that your decision must be absolutely correct or that a court or other body faced with the same facts would have reached the same decision. It means that in making the decision, you must have applied logical and rational principles.

The courts recognise that decision-making bodies have specialist expertise and knowledge in their given areas and that they should be free to make decisions without undue interference from the courts. The courts will generally only quash a decision on the ground of unreasonableness where:

  • it plainly and unambiguously flies in the face of fundamental reason and common sense (the Keegan test); or
  • there was no relevant material before the decision-making body to support the decision (the O'Keeffe test).

If the court finds that a decision is unreasonable, it will not remake the decision; it will usually quash it and send it back to the original decision-making body for a fresh consideration.


Mr O'Leary, a hunter, held a firearms licence for a .243 bolt action Ruger rifle. He sold the .243 rifle and purchased a.308 calibre hunting rifle. He applied to the local Superintendent to substitute his existing firearms certificate for the .308 rifle. The Superintendent refused his application, citing safety concerns. However, he indicated that he would be willing to grant him a licence for a 30-06 calibre rifle.

High Court: The Superintendent's decision was fundamentally at variance with common sense. He refused the licence for the .308 because it was a more powerful and heavier calibre rifle than the .243. Yet, he indicated that he would be willing to grant a licence for a 30-06 calibre rifle, which delivers a faster projectile than the .308. It is difficult to see how one rifle could be deemed too dangerous to the public, while another which delivers its rounds faster is viewed favourably (O'Leary v Maher).


  • Before you make a decision, carefully examine the source of your decision-making power and ascertain what you can and cannot do.
  • Make sure you have all the information you need. If you do not, get it.
  • Check that the facts on which you propose to base your decision are accurate and up to date.
  • Keep a written record of the factors that influenced your decision and that factors you considered irrelevant.
  • Apply logical and rational principles when making your decision.


In addition to complying with each of the above principles, decision-makers must apply fair procedures. We will discuss this in Guide 3.

This article contains a general summary of developments and is not a complete or definitive statement of the law. Specific legal advice should be obtained where appropriate.