'Glass ceiling' is the name given to structural barriers that impede women's access to top decision-making and managerial positions in organisations of all types and domains. The Glass Ceiling Index (GCI) is a relative index comparing the proportion of women in academia (grades A, B, and C) to the proportion of women in top academic positions (grade A positions, equivalent to full professorships in most countries) in a given year. The GCI can range from 0 to infinity. A GCI of 1 indicates that there is no difference between women and men for being promoted. A score of less than 1 means that women are over-represented at grade A level and a GCI score of more than 1 points towards a glass ceiling effect, meaning that women are under-represented in grade A positions. In other words, the interpretation of the GCI is that the higher the value, the stronger the glass ceiling effect and the more difficult it is for women to move into a higher position.
Available flags:
| b | break in time series | c | confidential |
| d | definition differs, see metadata | e | estimated |
| f | forecast | i | see metadata |
| m | imputed | n | not significant |
| p | provisional | r | revised |
| s | Eurostat estimate | u | low reliability |
| x | dropped due to insufficient sample size | y | unreliable due to small sample size |
| z | not applicable |