Plaintiffs appeal from a judgment dismissing their personal injury claims against defendant county.1 They argue that the trial court erred in ruling that their claims are barred by quasi-judicial immunity. We affirm.
Plaintiffs, a mother and daughter, were assaulted by Hough six days after his release from the psychiatric unit of the Multnomah County Detention Center. The release was made under a program ordered by the federal district court to relieve jail overcrowding. A court-ordered matrix system was to be used to evaluate the potential risk to the community if a particular inmate were released and was intended to result in the release of the least dangerous offenders. The court order set out the primary matrix factors and delegated authority to the sheriff to consider additional factors. One of the factors required to be considered was an inmate’s custody status, i.e., where he was confined. Before he was released, Hough was in the psychiatric unit. The order required court approval before the criteria could be amended.
Without first obtaining an approved amendment of the order, and contrary to the criteria promulgated by the sheriff pursuant to the order, county’s corrections officials decided not to include the custody status category in calculating inmates’ matrix scores. As a result, Hough was released from custody. Had the criteria established by the court, as implemented formally by the sheriff, been used, he would not have been released. At the time of his release, there were at least seven inmates, who had lower matrix scores than the improperly computed score of Hough, who were not released. Plaintiffs allege that the county was negligent in releasing Hough. The trial court granted the summary judgment on the ground that the release decision was a judicial function for which the county is immune.
Immunity for judicial acts extends to officials who are performing acts that are parts of the judicial process. When judicial functions are performed by a public official other than a judge, the immunity is called quasi-judicial immunity, but *399the distinction makes no difference. Whether immunity is recognized depends on the nature of the function being performed, Praggastis v. Clackamas County, 305 Or 419, 426-29, 752 P2d 302 (1988).
Calculation of Hough’s matrix score and authorization of his release were parts of the performance of a judicial function, because only judges are authorized to make release decisions and because the employes who actually released him were acting under the authority of the federal matrix release order. Their only authority was derived from the federal court and the federal judge. In applying the matrix, they were carrying out a judicial order and were thereby performing a judicial function. If they were not carrying out a judicial function, they were not carrying out any lawful function at all in the particular circumstances. In performing a judicial function, just as in performing any function, the actor can make a mistake or can be simply, simple-mindedly or even stupidly wrong. The function is still judicial.2
This case is unlike Utley v. City of Independence, 240 Or 384, 402 P2d 91 (1965). Here, county corrections personnel had authority to act — derived from the federal court; in Utley, the defendants could not identify any source from which any authority to act at all was derived. If county’s employes disobeyed their instructions, that was a matter between them and the federal court. It did not deprive them of immunity.
Affirmed.
Plaintiffs took a default judgment against defendant Hough. The court granted an ORCP 67B judgment against plaintiff on behalf of county. The City of Portland was voluntarily dismissed as a party.
In Praggastis v. Clackamas County, supra, 305 Or at 426, the Supreme Court stated:
“The common law recognized that there is a public good to be gained from the principled and fearless decision-making of judicial officers freed from concern over suits by disappointed litigants. To gain this good, it is necessary to cloak judicial officers with immunity from civil liability for their acts, so long as these acts are within the jurisdiction of the officer.”