Glossary >> Glossary of statistical terms Proxy indicators (or indirect indicators)  Refer to the subject of interest in an indirect way. For example, using statistics on the proportion of women in parliaments to assess women’s participation in public affairs. There are several reasons for working with proxy indicators: the subject of interest cannot be measured directly or it can but it is a sensitive issue such as income or safe sex and it may not be cost-effective to collect information on the actual indicator. A good proxy indicator has to weigh the reliability of the information and the efforts/resources needed to obtain the data. Qualitative indicator  In the context of this work, indicators expressed as a narrative, in categories or classes, and based on information on objects, facts or events that are, in principle, directly observable and verifiable (objective) or on information that is a perception, opinion, assessment or judgement (subjective). For example: status of ratification of an international human rights treaty (binary indicator: ratified or not ratified) and the classification of accreditation of national human rights institutions by the International Coordinating Committee of National Institutions (A: compliant with the Paris Principles; B: not fully compliant with the Paris Principles or insufficient information provided to make a determination; and C: not compliant with the Paris Principles). Quantiles  Points selected at regular intervals in a set of ordered data that divide them into “n” equal-sized subsets. Quantiles are data values that mark the boundaries between those subsets. For example, if “n” is 5 or 10, the set of ordered data is divided into 5 (quintiles) and 10 (deciles) subsets, respectively. If “n” is 2, the set of data is divided into 2 subsets, the data values that mark the boundary between the subsets is the median. For instance, if the median household income of a population is $500, it means that 50 per cent of households earn less than $500 and 50 per cent earn more than $500. Quantitative indicator  In the context of this work, indicators expressed in a numerical form, using categories or classes that are assigned numeric values, and based on information on objects, facts or events that are, in principle, directly observable and verifiable (objective) or on information that is a perception, opinion, assessment or judgement (subjective). For example: the maternal mortality ratio and the proportion of people who felt unsafe. The latter refers to people aged 18 years and over who felt unsafe when alone in at least one of the following situations: at home during the day or at night, when walking in their neighbourhood or taking public transport after dark. It includes people who were never alone in at least one of these situations because they thought it was unsafe. Rate (see also ratio)  Change in the value or quantity of a variable, generally per unit of time or with reference to a population unit. For example, change in the value of a variable or indicator compared to its value in an earlier time interval (prison population growth rate over a year). Similarly, the crime rate is the number of crimes committed (or reported) in an area to the population of that area, usually expressed per 100,000 persons per year. Ratio  The relationship between two quantities measured in the same unit, so that the resulting number has no unit. For example, the ratio of girls to boys in primary schools, computed as the number of girls in primary schools divided by the number of boys in primary schools. Any change over time in the value of a ratio needs careful examination. It may be owing to changes either in the numerator or in the denominator or both. In addition, in this case it may be necessary to also know the ratio of girls to boys of primary school age in the population to assess access or discrimination faced by girls. An index (number) is a ratio used for calculating the relative variation of the value of a number to its baseline value. The ratio is generally multiplied by 100 and the value 100 assigned to the index base. Indices can be used to measure the variation over time between one variable or several variables (composite index). One example is the consumer price index, which measures price changes experienced by consumers in maintaining a constant basket of goods and services over time. Human Rights Indicators 173