Skills, difficulty and source

Three properties describe what a problem is, apart from where it is filed:

Property	Values	Who sets it
Skill	What the problem practises, from one shared list: an area and a skill in it, such as Loops › while loops. A problem can have several.	The problem’s editors choose from the list; system administrators keep the list (Administration → Skills).
Difficulty	0–10, shown as a band with the number: Easy (0–2), Medium (3–4), Hard (5–10).	The problem’s editors.
Source	Where the problem comes from: Own, Exam, Olympiad, Contest, Textbook or Other, with an optional detail (such as “junior” or “stage III”) and year.	The problem’s editors.

They are library information only: students never see a problem’s skills or source, and changing them changes no course, version or result. The number behind a difficulty band is what the problem-solving mark uses, so it stays exact.

Skills replace the old curriculum folders: the topic folders imported from the old system (1.1–7) became skills, and the exam and olympiad folders became sources. The folders themselves are still there as collections.

Setting them on a problem

On the problem’s page, in the settings pane, the Skills and source card:

• Skills lists the problem’s skills as Area › Skill. Add skills or Change skills opens the list: tick the skills and click Save skills. A skill that has since been archived stays on the problem with an archive mark; untick it to take it off.
• Source: choose one, or Not recorded. With a source chosen, Detail and Year (1950–2100) appear; they are saved when you leave the field or press Enter.

Difficulty is in the Details card; its list groups the levels by band. Everything saves at once (Saving…, Saved); a refused change puts the previous value back and says why. Only the problem’s editors can change these cards (see Problem archive).

Filtering the archive

Above the problem list are three filters: Skill, Difficulty and Source. Each opens a list with the number of problems for every value, and a last item for problems without one (No skill, No difficulty, No source).

• Tick several values in one filter to see problems with any of them; filters together narrow the list (a problem must match each).
• Each number counts the problems that match all your other filters, so you can see what a choice would leave before you make it.
• The chosen values appear as chips under the filters; the chip’s × removes one, Clear filters removes them all.
• The filters are part of the address (?skill=…&band=easy,medium&source=exam), so a filtered list can be bookmarked or sent to a colleague.

The numbers only count problems you are allowed to see: someone else’s private problem is never counted, in any filter.

No skill is a quick way to find problems that still need classifying.

Setting them on many problems

1. Select problems in the list (their checkboxes, or Select all on this page).
2. In the bar at the top choose Skills… or Source….

Skills… lists every skill with a checkbox and how many of the selected problems have it (3/12):

Box	Meaning when you save
Ticked	Every selected problem gets the skill.
Empty	The skill is taken off every selected problem.
Dash	Some have it: each problem keeps what it has.

Clicking a box cycles through the choices. Source… sets one source (with detail and year) on every selected problem, or Not recorded to clear it.

Before you save, the dialog shows its plan: how many problems change, how many already match, and how many are left alone because you can’t edit them. Only those you may edit are changed; the rest are untouched. The selection stays, so you can set skills and then the source on the same problems.

Next

• Problem archive – the list, its other filters and row actions.
• Problem settings – every card of the settings pane.