# Editing Constraints

After you have added your preferred criteria, the next step is to decide on a value for the constraint of each variable.
Constraints will serve as a threshold to eliminate companies and limit your search.
Stocks with a value falling outside that threshold will be screened out of your table.

To set a constraint for a chosen variable, simply click once on any value in that variable's column and you will be forwarded to the page of constraints. To illustrate the process more explicitly, we shall return to the previous example and let us assume you wish to set a constraint for the variable of PE Ratio. To do so, click on any value in the column of the PE Ratio.

You now enter a new page, the page of constraints, which consists of two main parts.

On the right, you see a graphical representation of how the variable (in this case PE Ratio) is distributed among the companies under research. Above each quartile a % figure is marked, telling you what proportion of the stock universe has a price of PE Ratio within the respective range. For example, you can see that around 22% of companies have a PE Ratio between 15 and 20.

Also, on the graph you can see two important figures about PE Ratio: the median and the average.
The median is the PE Ratio value that divides the population of stocks in two equal halves. Assuming you deal with 100 companies, the median would be the price of PE Ratio for the 51st company.
The average is the arithmetic average value of the PE Ratio for the population of companies. Those two figures, which are automatically calculated, can prove quite useful when analyzing stocks and trying to identify the threshold value for the PE Ratio.

On the left, in the constraints page, you can see 3 statements, each bearing a tick-box to its left.
These allow you to set the level of constraint for the variable of PE Ratio. For example, you decide to exclude all the stocks with a PE Ratio of 15 or more, and also to exclude all stock with a PE Ratio of 5 or less. Type 15 as the constraint on the first statement, and type 5 as the constraint in the second statement. Tick their respective boxes so that the constraints are activated, and click on 'Submit'.

Instantly you return to the table of results, which now contains only those companies with a PE Ratio ranging from 5 to 15.
Note here that the page-meter reading is significantly different from the initial 105 pages. Rather than that, it shows something like ‘1 of 14 pages’, which means that there are roughly 1,400 companies in your stock universe that qualify for the constraint you have just set.

Another important thing you should notice here is that after setting the constraint for PE Ratio (PE Ratio between 5 and 15), the variable and its constraint appear on the area we earlier called the screen's monitor, directly above the table. In this area you can follow which constraints are currently in use. This also provides a quick way to jump into the constraints page for any variable, since the name of the variable in blue print is clickable. Try clicking on PE Ratio, and you will be directed to the constraints page again.

Now, note that the graph has changed to represent the distribution of PE Ratios among the 1,400 remaining companies. The median and average values are also different because they now refer to these 1,400 companies, but not the whole population of stocks, as it was initially the case. Now tighten the range to exclude companies with PE Ratio greater than 12 and less than 8, and click 'Submit' again. The table of results now consists of some 5 pages, or approximately 500 companies.

In a similar manner you proceed by setting constraints for the other variables. This limits the qualifying companies further and gradually builds the screen you wish.