measure
Measure microformat
Currently this microformat is in exploratory stage. Contributions should focus on real examples from the Web, existing formats/encoding of measures.
The problem
Measures (e.g. weights, sizes, temperatures) occur frequently on the Web, but they differ from locale to locale (e.g. Fahrenheit vs. Celsius, pound versus Kilogram) making comparison and matching of offerings difficult.
The Measurement Unit microformat will enable unambiguous description of measures and as a result easier comparison and matching of offerings.
Related microformats
- job-listing can use time measure for specify per what period of time the salary is for.
- hlisting product dimensions; weight/mass; time period (as above).
- directions-examples can use length measure for mileage and time to go from one point to the next.
- recipe-examples can use weight, volume and time measure for ingredients and preparation time.
- currency can be viewed as a measurement unit, or as a component of a measurement unit, as in $ per hour.
Measurement Classification
Because it is easier to provide examples, I will first list examples.
Categorical Data
- Various measurements may produce NON-Numerical values
- a pain scale: most severe, very severe, severe, ...
A Single Value / Data Point
- the distance between 2 cities is 40 km
- the velocity is 62 mph
- ...
An Interval Measurement
- time: the shop is open between 6am - 18pm on every day of the week, exept Saturdays from 9am - 16pm and Sundays from 9am - 13pm
- hCalendar? Andy Mabbett 09:24, 22 Nov 2006 (PST)
This is more about an interval measurement. Every variable can have 2 (or more) values, e.g.:
- the levels of rain fall were between 25mm - 35mm
- the maximum velocity of various cars was 220 - 250 km/h
Should these values be stored as separate values? [e.g. low / high] Or should the microformats be able to store an interval?
See also the examples for statistical summaries below.
Matrices
- the GPS coordinates are 12°14' N and 25°55' E
- Geo? Andy Mabbett 09:25, 22 Nov 2006 (PST)
- the dimension of the box is 3m x 2m x 0.55m
- this is three separate, single measurements, surely? Andy Mabbett 09:21, 22 Nov 2006 (PST)
Statistical Measurements
Often, a group of data is summarized using a statistics:
- the mean length was 1.3m (SD 0.12m, group size 22)
- the median age was 42 years (interquartile range 95% 18 - 97)
Measurement Scales
Accuracy vs. Precision
QUESTIONS
- How detailed should a measurement be stored?
- Microformats aren't for storing measurements; they're for "labelling" the measurements that are already present. Andy Mabbett 09:23, 22 Nov 2006 (PST)
- If Accuracy and precision are relevant to the measurement, how do we store these?
Standardization of Measurement
- sometimes we may need to store the calibration information / calibration curves
- we may need to store the reference point the measurement is based on
- we may need to store the normal values
- biomedical measurements are often laboratory dependent, so it does NOT make sense to have the measurement without the corresponding normal values
- e.g. anti-Hepatitis B surface antigen antibody (anti-HBs) Titer: 32 MIU/ml
- normal: 0 (non-infected, non-past infection, non-immunity)
- protective immunity: >10 MIU/ml
- interpretation is however more complex, depending on other tests as well
Contributors
- Guillaume Lebleu
- Andy Mabbett