Does the school performance variable used in the International Health Behavior in School-Aged Children (HBSC) Study reflect students' school grades?
The PSP item seems to be a valid and useful question that can distinguish groups of respondents that get good grades at school from those that do not. The meaning of PSP may be context-specific and may have different connotations across student populations from different countries with different school systems.
The most conserved pattern was observed at the amino acid level: strong alanine over-representation was observed at the second amino acid position of highly expressed proteins. This pattern is well conserved in all three domains of life.