[U5Q] Ricаrdо wаnts tо increаse his client Marell’s silent reading ability. Ricardо tracks the total number of pages Marell reads each day. Initially, Marell does not read any pages at all, so Ricardo sets 5 pages as the minimum number of pages Marell needs to read to earn a daily reinforcer. For the next 5 days, Marell reads between 4–9 pages and meets the minimum requirement on 4 out of 5 days. Ricardo then sets 7 pages as the minimum number of pages Marell needs to read daily. Marell continues to meet the minimum number of pages read by reading between 7–15 pages a day. Ricardo then sets 12 pages as the minimum number of pages Marell needs to read to earn a daily reinforcer. What should Ricardo consider when using a changing criterion design?