Title: Cell (Total) percentages
Course: UGQuants (SSPS) > Section: Associations Between 2 Variables

Cell (total) percentages

While column and row percentages take as their starting points the variables shown, respectively, in the columns and rows of the table, with cell percentage (or ‘total’ percentage) the focus is on individual cells, or to put it another way, combinations of values of the two variables. If this initially seems the same or very similar to the data shown in the cells for column and row percentage, then the difference is that while these percentages show the data as a percentage of all cases in a particular column or row, cell percentage shows the number of cases in each cell of the table as a percentage of all cases shown in the table. The best way to grasp this concept is to repeat table 1 showing the counts of cases, but this time with the value for cell percentage added in each cell showing the possible combinations of values for the two variables. This is shown in table 4.

Table 4: Cigarette smoking in England by whether respondent has university degree

(counts and cell percentage to the nearest 1%)

Currently smokes cigarettes? | Has University degree
Degree | No Degree | All
Smoker | 171 5% | 1010 29% | 1181
Non-Smoker | 633 18% | 1717 49% | 2350
Total | 804 | 2727 | 3531

Source: Health Survey for England, 2010

Table 4 shows that, of all cases represented in the table, only about 5% smoke cigarettes and have a degree. Another useful way to understand this might be to think of it in terms of probability: if we selected an individual at random from all those represented in table 4, there is only about a 1 in 20 chance that person would both have a degree and be a smoker. On the other hand, there would be about a 1 in 2 chance (‘evens’ in the language of odds) that our random selection would turn out to be someone who did not have a degree and did not smoke, because the table tells us that this category represents approximately 49% of all cases.

We can also recognise cell percentages by adding together all the cell percentages in a table: when we do this, they should sum to (approximately) 100%.