Almost nobody admits to this one. It sounds petty in a way that being jealous of a partner does not, so it gets carried privately, updated quietly at every wedding and Christmas, and never said out loud. It is also close to universal, and there are good structural reasons for it that have nothing to do with being a small person.
What is usually going on
You were sorted young, and the categories stuck. Families hand out roles early and rarely revise them: the clever one, the easy one, the sporty one, the one who worries everybody. These labels are assigned on thin evidence at an age when the differences are mostly developmental, and then they become self-fulfilling, because the sibling who was not the clever one stops competing in that lane and the sorting looks confirmed.
Your sibling is the only genuinely controlled comparison you have. Compare yourself to a colleague and there are a hundred confounds — different parents, different money, different schooling. Compare yourself to a sibling and most of that is held constant, so the remaining gap seems to be about you personally. This is exactly why the comparison stings more than any other, and the logic is wrong: siblings raised in the same house are far less alike than the intuition predicts, and the research on shared and non-shared environment is the reason. The environment that shapes a person is largely the part they did not share — different friends, different teachers, a different position in the family, a different year in which the parents were struggling.
Your parents are still keeping score out loud. Some of this is not internal at all. Where a parent audibly compares, the rivalry is being actively maintained, and no amount of private work on your own attitude will settle something that gets refreshed at every family lunch.
The comparison is being run on visible metrics only. House, job title, wedding, children, holidays. These are the measures that survive the family group chat, which means the scoreboard consists entirely of the things easiest to photograph and worst at predicting how anybody's life is actually going.
There is an old, unpaid debt underneath it. Sometimes what looks like envy of a sibling's success is a much older grievance about how attention was distributed, and the sibling is simply the nearest available object. That one does not resolve by out-earning them.
What to do
- Notice which metric you use. Almost everyone has exactly one — money, or status, or whose life looks more settled. It is usually the metric your family rated most highly, which means you are still being marked by a marking scheme you did not choose.
- Stop competing in a lane you were assigned. If you were the practical one and have spent twenty years proving you are also clever, that is a long project in someone else's category.
- Get a scale that is not them. Percentiles against a population are a strange relief the first time you see them — the entry on percentiles and norms explains why a score only means anything against a group, and one sibling is not a group.
- Say one true sentence to them, if the relationship can hold it. I think I've been comparing myself to you for about twenty years and it's a stupid way to live. Siblings very often turn out to have been doing the same thing from the other direction, frequently about the qualities you assumed they had no interest in.
- Do not expect your parents to referee it. Asking a parent to confirm you were treated unequally puts them in a position almost nobody handles well, and the answer will not settle it either way.
What it depends on
The comparison feels like a ranking, and it is almost always a difference in traits being read as a difference in worth. A sibling who is higher on extraversion will have more visible social life. One higher on conscientiousness will have a tidier-looking career and may also have a harder time stopping. Neither of those is a better person; they are different settings on the same five dials, and the trade-offs are real in both directions.
That is the specific use of the Big Five test here. It gives you a profile with no better or worse end, scored against thousands of people rather than against one, and it tends to dismantle the sorting that a family did to you at the age of nine — because it shows you were never on one scale to begin with.