# Decoding statistics help please. **URL:** \ **Category:** Factual Questions\ **Created:** [October 5, 2015, 4:44pm UTC](https://boards.straightdope.com/t/decoding-statistics-help-please/733623 "2015-10-05T16:44:11Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![curious11](https://avatars.discourse-cdn.com/v4/letter/c/ac91a4/32.png) [@curious11](https://boards.straightdope.com/u/curious11)\ **Post date:** [October 5, 2015, 4:44pm UTC](https://boards.straightdope.com/t/decoding-statistics-help-please/733623/1 "2015-10-05T16:44:11Z")
Hey All, What does the 0.55 mean in the following line. “The adjusted relative risk for injury to blah-blah-blah compared with those in bleh-bleh-bleh was 0.55” Obviously the 0.55 means that the injury risk is higher in the bleh-bleh-bleh case, but how much higher does 0.55 mean? What number would be the same risk? 0.00? 0.50? ---
**Author:** ![mcgato](https://avatars.discourse-cdn.com/v4/letter/m/ac8455/32.png) [@mcgato](https://boards.straightdope.com/u/mcgato)\ **Post date:** [October 5, 2015, 5:25pm UTC](https://boards.straightdope.com/t/decoding-statistics-help-please/733623/2 "2015-10-05T17:25:54Z")
Not really my area, but I believe that a relative risk of 1 means that the two groups have the same risk. Lower numbers mean lower risk for a given group. A relative risk of 0.55 is about half the risk. ---
**Author:** ![bob\_2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bob_2/32/3341_2.png) [@bob\_2](https://boards.straightdope.com/u/bob_2)\ **Post date:** [October 5, 2015, 10:13pm UTC](https://boards.straightdope.com/t/decoding-statistics-help-please/733623/3 "2015-10-05T22:13:28Z")
I always have problems with x% more and y% less. What does a sign that says “up to 50% off”? Actually I have no problem with the arithmetic, but often, people who say these things, don’t. ---
**Author:** ![septimus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/septimus/32/410_2.png) [@septimus](https://boards.straightdope.com/u/septimus)\ **Post date:** [October 6, 2015, 5:28am UTC](https://boards.straightdope.com/t/decoding-statistics-help-please/733623/4 "2015-10-06T05:28:25Z")
> [@curious11](#): > > “The adjusted relative risk for injury to blah-blah-blah compared with those in bleh-bleh-bleh was 0.55” > > Obviously the 0.55 means that the injury risk is higher in the bleh-bleh-bleh case, but how much higher does 0.55 mean? > > What number would be the same risk? 0.00? 0.50? I don’t think so. Relative risk of 0.55 means the blah-blah are only 55% as likely to be injured as bleh-bleh. The ratio would be 1.0 if the risks were the same. The “adjusted” in _adjusted relative risk_ might refer to various adjustments but I think means that the numbers have been fiddled to make them _more_ valid, not less! ---
**Author:** ![Patty\_O\_Furniture](https://avatars.discourse-cdn.com/v4/letter/p/96bed5/32.png) [@Patty\_O\_Furniture](https://boards.straightdope.com/u/Patty_O_Furniture)\ **Post date:** [October 6, 2015, 12:52pm UTC](https://boards.straightdope.com/t/decoding-statistics-help-please/733623/5 "2015-10-06T12:52:39Z")
> [@bob\_2](#): > > I always have problems with x% more and y% less. What does a sign that says “up to 50% off”? That means it could be as much as twice as cheap. ---
**Author:** ![Buck\_Godot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/buck_godot/32/6573_2.png) [@Buck\_Godot](https://boards.straightdope.com/u/Buck_Godot)\ **Post date:** [October 6, 2015, 2:58pm UTC](https://boards.straightdope.com/t/decoding-statistics-help-please/733623/6 "2015-10-06T14:58:31Z")
55% Relative risk means the probability of having an event at a particular instant in time under situation A is 55% of what it is in situation B. Equal risk would be a value of 1.0. Note this doesn’t mean that the overall chance of having that event is less, it may mean that you are more likely to go longer before it occurs… As an illustration of this, suppose that every day you roll a die and on a roll of a 6 you die. Meanwhile your friend is in a worse situation and so every day he rolls the die and is killed on the roll of either a 5 or a 6. You would have a relative risk of compared to him of 50% but both of you are have a near 100% likelihood of dying within the next month. ---
**Author:** ![curious11](https://avatars.discourse-cdn.com/v4/letter/c/ac91a4/32.png) [@curious11](https://boards.straightdope.com/u/curious11)\ **Post date:** [October 6, 2015, 4:02pm UTC](https://boards.straightdope.com/t/decoding-statistics-help-please/733623/7 "2015-10-06T16:02:50Z")
Thanks!