across the board

meaning: it applies to everyone; everyone will have to do it

1. We have some new rules, and these apply across the board, so the teachers will have to follow them too.

2. After a disastrous last year, they made changes across the board.
acid test

meaning: the conclusive test that will prove whether a plan/product/programme is a success

1. The numbers work in theory, but the acid test will be when the product goes on the market.

2. They are top of the league after half a season, but the acid test will be February when they play their four main rivals. Then we will know whether they are potential champions.

3. The company is looking good now, but the acid test will come when consumers get bored of this product. If they can produce a second wave of items that continue to get attention, and still make money, then we’ll know it is here to stay.