Statistics in Descriptive Research

The description of a sample implies that a researcher defines variables, measures them, and for each measure calculates one or more of the following descriptive statistics: measures of central tendency and measures of variability. Measures of central tendency are: mean, median and mode. Measures of variability are: standard deviation, variance and range. The researcher can also calculate the derived scores which help interpreting the sample's scores on the variables that were measured. Derived scores aid the interpretation by providing a quantitative measure of each individual's performance relative to a comparison group. Age equivalents, grade equivalents, percentiles, and standard scores are examples of derived scores commonly used in descriptive research.

Some descriptive research provide statistical information about aspects of education that interest  policy makers and educators. This type of research is the specialty of the National Center for Education Statistics. Many of this center's research results are published in an annual volume called the Digest of Educational Statistics. This center also administers the National Assessment of Educational Progress (NAEP), which is a collection of descriptive information about the performance of youth in the different subjects taught in public schools. A noticeable NAEP publication is the Reading Report Card, which reports descriptive statistics about student's performance in reading at different levels. At a higher level the International Association for the the Evaluation of  Educational Achievement (IEA) does descriptive studies of the academic achievement of students in many nations including the United States.

The two main types of descriptive research differ by the time the variables are measured. In the first type the variables or the characteristics of a sample are measured at one point in time. In the second type which is called longitudinal a sample is followed over time.    

The Purpose of Descriptive Research

The most basic form of Research involves the description of the forms, actions, changes over time of the natural and non-natural phenomena. It also involves the description of similarities with other phenomena. The description of phenomena has led scientists to many scientific discoveries. For example the description of some parts of the universe by astronomers have led to the discovery of the structure of the solar system and the prediction of lunar eclipses.

Descriptive research in education involves the description of educational phenomena. Description viewed in research as understanding what people or things mean is an important goal in qualitative research. For this reason it is important  to know the qualitative and quantitative approaches in the planification of descriptive studies. This allows to make the best choices in undertaking descriptive research.

Descriptive studies primarily determine "what is". As examples some of the possible questions of being studied in descriptive studies are: What kinds of activities occur in a ninth grade science class and how frequently do they occur? What were the reactions of school administrators to innovations in teaching Biology?

Most educational studies tend to discover cause and effect relationships and testing new educational methods and programs. Researchers have to describe an educational phenomenon first before attempting to explain or change it. Some educational reforms took place with the findings of some descriptive studies. Some educational books like Life in Classrooms by Philip Jackson, The Good High School by Sara Lawrence Lightfoot and A Place Called School are based on descriptive studies.

Researchers administer questionnaires and interviews to a sample of research participants in order to collect data for their descriptive studies. This type of research called survey research leads to knowledge of opinions, attitudes and practices. Such knowledge has helped in shaping educational policies and initiatives to change existing conditions.

In summary the description of natural and non-natural phenomena involves the description of their forms, actions, changes over time and similarities with other phenomena. This type of research has led to important discoveries in astronomy. The description of different parts of the universe has led to important discoveries about this universe. Descriptive research viewed as understanding what people or things mean is used both in quantitative and qualitative research. Descriptive research means also understanding what exists by asking questions. Descriptive educational studies tend to discover cause and effect relationships and testing new educational methods and programs. Many educational reforms took place with the results of descriptive research studies. Some books written by educators are the results of descriptive studies. Researchers use questionnaires and interviews to collect data about their descriptive studies. The findings of such studies lead to the establishment of policies and initiatives to change conditions. It can be noted that conditions can be worsened if it is poorly designed and its philosophy doesn't lead to results that truly benefits the majority of people. Such type of research can lead to authoritarian and non democratic policies that don't lead to meaningful changes for the majority but reinforce the privileges of a minority.         

Classification of research designs

Quantitative researchers have developed different types of research designs to facilitate their studies. Their research procedures include organization of the variables, selection of samples, schedule for data collection and techniques for statistical analysis.

Similarities between research designs have allowed to to classify them in various types. The criteria of the use of experiment have allowed to classify the designs in experimental and non-experimental research.  In non- experimental design the researcher studies existing phenomena without intervention in the structure of these phenomena. On the other hand the experimental design require some kind of experiment with the intervention of the researcher. The various types of non-experimental design are: descriptive, causal-comparative and correlational.

Research designs are also classified according to their purpose. Educational studies are undertaken according to four different purposes: description, prediction, improvement and explanation.

If the purpose is description, two types of research design can be used: descriptive and longitudinal. Descriptive research is used when phenomena are studied at one point in time. Longitudinal design is used to study changes that occur in phenomena over time.

If the purpose is prediction, correlational design is used.

When the purpose is explanation a causal-comparative design is used. The design involves finding cause and effect relationships between variables. Correlation and experimental design are also used. I would also add that descriptive design can be used because when you describe something you also explain it.

Finally if the purpose of the design is improvement, experimental design is used.  The reason why experimental design is used is because designing an intervention and following its effects is a kind of experiment.