Face validity refers to the degree to which an assessment or test subjectively appears to measure the variable or construct that it is supposed to measure. In other words, face validity is when an assessment or test appears to do what it claims to do.
Step 2: Using an electronic detector, check that the area of wall where you plan to hang the shelves is free from hidden pipes or cables. Step 3: Place your first bracket against the wall, using a spirit level to make sure it's level. Mark the fixing-hole positions with a pencil.Step 4: Using the pencil marks, drill holes into the wall.crew the bracket into place. Step 5: Slide the shelf onto the bracket to check that it's level (use the spirit level to make sure). Once you're happy with the position of this shelf and the way it looks, slide it back off the bracket so that you can position the rest of the brackets.
Bookshelf Shelf Spacing and Depth of Shelves. Each shelf in a bookshelf is set at a particular height depending on what type of book the shelving holds. For magazines, shelves are set 11 inches apart. For books, the shelves are spaced 10 inches apart.