From Pope St. John Paul II’s Apostolic Exhortation Reconciliatio et Pænitentia (1984):
Following the suggestions of the Second Vatican Council, the Ordo Pænitentiæ provided three rites which, while always keeping intact the essential elements, make it possible to adapt the celebration of the sacrament of penance to particular pastoral circumstances.
The first form—reconciliation of individual penitents—is the only normal and ordinary way of celebrating the sacrament, and it cannot and must not be allowed to fall into disuse or be neglected. The second form—reconciliation of a number of penitents with individual confession and absolution—even though in the preparatory acts it helps to give greater emphasis to the community aspects of the sacrament, is the same as the first form in the culminating sacramental act, namely individual confession and individual absolution of sins. It can thus be regarded as equal to the first form as regards the normality of the rite. The third form however— reconciliation of a number of penitents with general confession and absolution—is exceptional in character. It is therefore not left to free choice but is regulated by a special discipline.
The first form makes possible a highlighting of the more personal—and essential—aspects which are included in the penitential process. The dialogue between penitent and confessor, the sum of the elements used (the biblical texts, the choice of the forms of “satisfaction,” etc.), make the sacramental celebration correspond more closely to the concrete situation of the penitent. The value of these elements is perceived when one considers the different reasons that bring a Christian to sacramental penance: a need for personal reconciliation and readmission to friendship with God by regaining the grace lost by sin; a need to check one’s spiritual progress and sometimes a need for a more accurate discernment of one’s vocation; on many other occasions a need and a desire to escape from a state of spiritual apathy and religious crisis. Thanks then to its individual character, the first form of celebration makes it possible to link the sacrament of penance with something which is different but readily linked with it: I am referring to spiritual direction. So it is certainly true that personal decision and commitment are clearly signified and promoted in this first form.
The second form of celebration, precisely by its specific dimension, highlights certain aspects of great importance: The word of God listened to in common has remarkable effect as compared to its individual reading and better emphasizes the ecclesial character of conversion and reconciliation. It is particularly meaningful at various seasons of the liturgical year and in connection with events of special pastoral importance. The only point that needs mentioning here is that for celebrating the second form there should be an adequate number of confessors present.
It is therefore natural that the criteria for deciding which of the two forms of celebration to use should be dictated not by situational and subjective reasons, but by a desire to secure the true spiritual good of the faithful in obedience to the penitential discipline of the church.
— Reconciliatio et Pænitentia 31