Source: National Cancer Registry of Ireland
Creator: Information Unit, Department of Health

The data contains National Cancer Registry Summary data by area and site (classified by ICD-10 codes) are provided. This includes European Age Standardised Rates (EASRs) that are accompanied by 95% confidence limits. The calculation of rates and confidence limits has been carried out by the National Cancer Registry of Ireland (NCRI). A total of 116 ICD-10 categories are covered. 'All Registered Neoplasms' is a separate category. The data cover the years from 1994 to 2010. All neoplasms (including in situ, uncertain and some benign neoplasms) registered as incident between January 1st and December 31st each year are included. Data for 2010 and for the combined 2006-2010 total are provisional and may change. All neoplasms (including in situ, uncertain and some benign neoplasms) registered as incident between January 1st and December 31st each year are included.

Interpret these data cautiously. As a general rule, this website does not include confidence limits in its charts and maps. It aims to provide visual tools that allow you to explore an underling table or dataset. If you find something that you think is important, we strongly urge you to explore it more rigorously – consulting an experienced data analyst if appropriate – before taking any action based on that finding.

1. Statistical precision
Indicator values are prone to statistical error (the difference between an estimated value and the true value). The statistical error associated with an indicator depends on the population subgroup (e.g. the population of a county or LGD) that it refers to. Such differences in levels of statistical error can distort what we see in maps and charts. They can make some relationships involving indicators and attributes appear “real” (practically meaningful or statistically significant) when they are in fact spurious; other relationships that are “real” can be masked. These differences in statistical error can even distort the shape of plots or the colour patterns we see in maps.

For example,

• Many indicator values estimates are derived from sample surveys, and different sample sizes from different population subgroups will lead to different levels of precision in the indicator values for these subgroups.
• Different population subgroups have different population sizes which means that rate estimates for these subgroups will also have different confidence limits.
• The true value of a percentage or a rate can influence the level of statistical error of any estimate.

2. Scales and legends
The scales used on chart axes and in can also distort our perceptions:

• The range of values allowed on chart axes can accentuate relationships making them appear more “real” than they actually are.
• The radial arms of spider plots of scaled data show the position of the value (in a population subgroup) relative to the minimum and maximum values of that indicator. Because these minimum and maximum depend on the indicator, relative positions of different population subgroups on different radial arms are not directly comparable.
• The cut-off values used to determine the colours to shade areas of a map are default selections and do not necessarily represent meaningful values of the indicator. Areas with very similar data values can be shown with different shades. You should always note the actual values.