Showing posts with label Research. Show all posts
Showing posts with label Research. Show all posts

Friday 24 February 2017

Experimental, Non-experimental, Descriptive, & Causal-comparative Research

Experimental research:

Experimental research

It is the research in which the researcher manipulates the independent variable and is interested in showing cause and effect.

The purpose of experimental research is to determine cause-and-effect relationships. The experimental research method enables us to identify causal relationships because it allows us to observe, under control conditions, the effects of systematically changing one or more variables.

Non-experimental research:

In non-experimental research, there is no manipulation of an independent variable. There is also no random assignment to groups by the researcher.

As a result of these two deficiencies (no manipulation and no random assignment), evidence gathered in support of cause-and-effect relationships in non-experimental research is severely limited and much weaker that evidence gathered in experimental research.

If the researcher wants to study cause and effect, he/she should try to conduct an experiment, but sometimes this is not feasible. When important causal research questions need to be answered and an experiment can’t be done, research must still be conducted. In research, we try to do the best we can.

For example, during the 1960s, extensive research linking cigarette smoking to lung cancer was conducted. Experimental research with humans was not possible because it would have been unethical. Therefore, in additional to experimental research with laboratory animals, medical researchers relied on non-experimental research methods for their extensive study of humans.

Descriptive Research:

Descriptive Research:

A descriptive study describes and interprets what is. It is concerned with conditions or relationships that exist, opinions that are held, processes that are going on, effects that are evident, or trends that are developing.

Descriptive study deals with the relationships between variables, the testing of hypotheses, and the development of generalizations, principles, or theories that have universal validity.
Descriptive study is sometimes divided into correlational research, causal-comparative research, and other descriptive research that is neither correlational nor designed to find out causation but describes existing conditions.

In carrying out a descriptive research project, in contrast to an experiment, the researcher does not manipulate the variable, decide who receives the treatment, or arrange for events to happen. Descriptive research also involves events that have already taken place and may be related to a present condition.

Descriptive research seeks to find answers to questions through the analysis of variable relationships. What factors seem to be associated with certain occurrences, outcomes, conditions, or types of behaviors?

Because it is often impracticable or unethical to arrange occurrences, an analysis of past events or of already existing conditions may be the only feasible way to study causation. This type of research is usually referred to as ex-post facto or causal-comparative research or, when correlational analyses are used, as correlational research.

Causal-comparative research:

In causal-comparative research, the researcher studies the relationship between one or more categorical independent variables and one or more quantitative dependent variables.

Because independent variable is categorical (that is males vs females, parents vs non-parents, or public school teachers vs private school teachers), the different group’s average scores on a dependent variable are compared to determine whether a relationship is present between the independent variable and dependent variable.

Despite the presence of the word causal included in the term causal-comparative research, one must keep in mind that causal-comparative research is a non-experimental research method, which means that there is no manipulation of an independent variable by a researcher.

Because of lack of manipulation and weaker techniques of controlling for extraneous variables, it is much more difficult to make statements about cause and effect in causal-comparative research than in experimental research.

What are various types of Variables?

Types of Variables:

Before explaining the types of variables, let's understand first the concept of variable and constant in educational research. Then after, we will discuss the types of variables.  

Variables Research

A variable is a condition or characteristic that can take on different values or categories. A much-studied educational variable is intelligence, which varies from low to high for different people. Age is another variable.

A constant is a single value or category of a variable. The variable gender is a marker for two constants: male and female. The category (that is constant) male is a marker for only one thing; it is one of the two constants forming the variable called gender. Gender varies, but male does not vary. Therefore, gender is a variable, and male is a constant.

Now, let's understand the types of variables. Following are the major types of variables which are being used in educational research.  

Quantitative variable: It is a variable that varies in degree or amount. It usually involves numbers.

Categorical variable: It is a variable that varies in type or kind. It usually involves different groups.

Independent variable: It is a variable that is presumed to cause a change to occur in another variable.

Dependent variable: It is a variable that is presumed to be influenced by one or more independent variables. The dependent variable is the variable that is “dependent on” the independent (that is antecedent) variable(s).

A cause-and-effect relationship between an independent variable and dependent variable is present when changes in the independent variable tend to cause changes in the dependent variable. Sometimes researchers call the dependent variables an outcome variable or a response variable because it is used to measure the effect of one or more independent variables.

What are the “Research Paradigms”?

What are the “Research Paradigms”?
Research Paradigms

Research is always a planned, systematic and rigorous activity in order to make known whatever is unknown to others and/or verify whatever is already known. It is action oriented. In other words, it can be defined as a systematic investigation into and study of materials and sources in order to establish facts and reach new conclusions.
As far as research paradigm is concerned, it is a perspective about research held by a community of researchers. The perspective is based on a set of shared assumptions, concepts, values, and practices. More simply, it is an approach to thinking about and doing research.
There are three major educational research paradigms or approaches: quantitative research, qualitative research, and mixed research.
The either-or position (that is, one must use quantitative or qualitative research but not both) is called the incompatibility thesis.
Pure quantitative research relies on the collection of quantitative data (that is numerical data) and follows the other characteristics of the quantitative research paradigm.
Pure qualitative research relies on the collection of qualitative data (that is, non-numerical data such as words and pictures) and follows the other characteristics of the qualitative research paradigm.
Mixed research involves the mixing of quantitative and qualitative research methods, approaches, or other paradigm characteristics.

Sunday 19 February 2017

Non-random Sampling Techniques

Non-random Sampling Techniques
Non-random Sampling Techniques
Sampling is the process of drawing a sample from a population. When we sample, we study the characteristics of a subset (called the sample) selected from a larger group (called the population) to understand the characteristics of the larger group.
There are random (also called probability) and non-random (also called non-probability) sampling techniques.
In non-random sampling or non-probability sampling, the units are selected at the discretion of the researcher. Such samples use human judgment in selecting units. While selecting the sample, the researcher only thinks where he will get the required data to serve his research purpose.
Such samples are used in the situations where the researcher does not want a representative sample. The researcher wants to gain insight into the problem by selecting only informed person who can provide him the maximum degree of insight into his problem with comprehensive information.
Quota Sampling: In this method, quota of sample from different units of the population is fixed and thus, total sample is selected.
Convenient Sampling:  In this method, whosoever is available to cooperate for providing information is selected and thus, the required number of sample is obtained.
Snowball Sampling: It is used to find subjects of interest from those who are most likely to be able to identify them. In this technique, the researcher uses few subjects to identify the other individuals who might be appropriate for the study. This continues with the new subjects, until the researcher has a sufficient and desired sample size.
Purposive Sampling: In purposive sampling, the researcher specifies the characteristics of a population of interest and then tries to locate individuals who have those characteristics. For example, a researcher might be interested in adult females over the age of 35 who are enrolled in a adult education program. Once the group is located, the researcher asks those who meet the inclusion criteria to participate in the research study.