OLCreate: Glossary

Glossary

Browse the glossary using this index

Special | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | ALL

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A

aggregation (data)

Data summarised into a group or class.

alternative hypothesis

A formal statement that there is a difference in an outcome between two or more groups.

anonymisation

The process of removing identifying information from a record.

antimicrobial consumption (AMC)

The quantity of antimicrobial drugs imported, manufactured and/or sold for use in human or veterinary medicine in a country. Typically expressed as 'defined daily dose'.

antimicrobial resistance (AMR)

Resistance, innate or acquired by, a microbe (most often, a bacterium) to any compound that is designed to kill It or inhibit its growth. Several different mechanisms of antibiotic resistance exist.

antimicrobial use

The quantity of antimicrobial drugs prescribed or administered to an individual person or animal, or group of animals (e.g. herd, flock), measured at the level of healthcare facility, farm, region or country. Typically measured as kg of antibiotics.

arithmetic mean

The sum of all values divided by the number of values, also known as the ‘average’.

B

bimodal

A data distribution that has two peaks.

C

categorical

Variable that can be classified into two or more categories that are mutually exclusive.

central tendency

A single value that attempts to describe a set of data by identifying the central position within that set of data.

chi-squared test

A statistical test that compares two or more variables in a contingency table to see if they are related.

confidence intervals (CIs)

The range of values within which if a study were repeated an infinite number of times under the same conditions, a specified percentage (often 95%) of the values obtained from these studies would be found.

confounding

An error of interpretation that arises when the apparent association between an exposure and an outcome variable is distorted by the presence of a third variable that is associated with both the exposure and the outcome.

D

data

Any observation or set of observations or measurements that represent attributes about an entity, also referred to as a data unit.

data collectors

A person whose job is to plan, manage and implement the entry of data into databases.

data management

A set of processes for preparing collected data into a form suitable for analysis.

data providers

A person or organisation that submits data to a database.

dataset

A collection of separate pieces of data that is treated as a single unit by a computer. Datasets often represent data in the form of a data table, in which columns represent variables, and rows represent data values corresponding to each data unit.

data unit

An entity, such as a person, or a farm, for which observations or measurements can be made.

descriptive statistics

Analysis of data that helps describe, show or summarise data in a meaningful way.

disc diffusion

A method of testing antibiotic effectiveness by placing paper discs infused with antibiotics on top of an agar plate spread with bacteria.

dispersion

The extent to which a data distribution is stretched or squeezed.

E

exposure variable

A variable that represents a risk factor for an outcome.

G

geometric mean

The n^th root of the multiplication product of the values, where n is the number of values.

I

indicator

A variable that has attributes directly relevant to decision-making.

inferential statistics

Analytical tools and tests used to make predictions about the population using data from a sample.

interquartile range

The difference between the 25^th and 75^th percentiles of a data distribution.

isolates

A bacterial strain separated from a mixed population of microbes such as those found in the soil or inside the gut. In the context of AMR surveillance, this will be a strain we are interested in because we want to know if it is resistant to one or more antimicrobials.

L

linear regression

A model of the relationship between a continuous outcome variable and one or more exposure variables generated by fitting a linear equation to observed data.

logistic regression

A model of the relationship between a binary (categorical) outcome variable and one or more exposure variables.

M

Mann-Whitney U test

A statistical test used to compare differences between two independent groups when the outcome variable is either ordinal or continuous, but not normally distributed.

mean

See arithmetic mean.

median

The middle value in an ordered set of values.

minimum inhibitory concentration (MIC)

A quantitative measure of the sensitivity of particular microbes to an antibiotic. Defined as the lowest concentration of an antimicrobial agent that inhibits the visible growth of a microorganism.

mode

The most common value in a set of values.

N

normally distributed

A symmetrical data distribution in which the mean, median and mode are equal; informally known as a ‘bell curve’.

null hypothesis

A formal statement that there is no difference in an outcome between two or more groups.

numeric

Data that can be represented as counts or measurements.

O

outcome variable

A variable that has values that change in response to the values of independent (also called exposure) variables.

P

parametric

A branch of statistics which assumes that sample data comes from a population that can be adequately modelled by a probability distribution that has a fixed set of parameters.

percentiles

A categorisation calculated by ordering the set of values and divided it in parts of more-or-less equal sizes (with the same number of values inside).

point prevalence survey (PPS)

A standardised methodology for measuring antimicrobial use in hospital inpatients.

proportions

Mathematically, part of a number in comparison to the whole.

p-value

A measure of the probability that an observed difference could have occurred due to chance.

Q

quartile

A type of percentile that divides the number of data points into four parts.

R

random error

Difference between a measured value and the true value that arises due to chance alone. In general, the smaller the sample size, the larger the random error.

range

The difference between the minimum and maximum observed values.

S

skewed

A distribution where the data points cluster more toward one side of the scale than the other, creating a curve that is not symmetrical.

statistical power

The probability of finding a statistical association where one exists (i.e. the probability of a true positive result). Larger sample sizes result in more power.

systematic bias

Error that represents a consistent deviation from the true value, which can arise during design, data collection, data management or analysis stages in surveillance systems or studies.

systematic error

See systematic bias

V

variable

Any characteristic or attribute of a data unit that can be measured.

variance

A measure of how far on average each value in the set of values is from the mean.