After the creation of the rating system, the board found that the M category (mature) was regarded by most parents as a sterner rating than the R (restricted) category. To remedy this misconception, the rating was changed from M to GP (general audiences, parental guidance suggested). A year later the name was revised the name to its current label, PG: (parental guidance suggested).

In July of 1984 the PG category was split into two groups - PG and PG-13. PG-13 meant a higher level of intensity than was to be found in a film rated PG. Over the past years, parents have approved of this amplifying revision in the rating system. In September of 1990 two more revisions were announced. First, the board began giving brief explanations of why a particular film received R ratings. Since, in the opinion of the Ratings Board, R rated films contain adult material, they believed it would be useful for parents to know a little more about that film’s content before they allowed their children to accompany them. Sometime later the board began applying the same explanations in the PG, PG-13 and NC-17 categories as well. These explanations are available to parents at the theater (by telephone or at the box office), in certain media reviews and listings, and also made available at

The second, change was in the X category which became NC-17 (no one 17 and under admitted). The X rating over the years appeared to have taken on a surly meaning in the minds of many people, a meaning that was never intended when the system was created. Therefore, the board chose to reaffirm the original intent of the design that was installed on November 1, 1968, in which the adults only category explicitly describes a movie that most parents would want to have barred to viewing by their children. These ratings were all trademarked and can only be used to for film ratings.