1. Validity refers to the degree to which a tool measures what it is intended to measure. There are several types of validity including content validity, criterion-related validity, and construct validity. 2. Reliability refers to the accuracy and consistency of a measuring tool. A reliable measure produces nearly the same results during repeated measurements. 3. Sensitivity refers to a measure's ability to detect changes, while appropriateness means a measure evaluates what it is intended to without bias. Objectivity, economy, practicability, and interest are also important factors when selecting a measurement tool.

2. 1.VALIDITY
Refers to the degree to which the tool measures
what it is intended to measure. Weighing scale measures
body weight and its valid; a tool which is valid for one
measure, need not be valid for another.

3.  TYPES:
a) Content validity:
This is concerned with the sampling
adequency of the content area being measured.
They also point out errors in items and make
recommendations for changes.
b) Criterion related validity:
Correlates with another criterion. e.g, anxiety during
exam.
They are two type i.e, predictive(admission test
predict the future of student) and concurrent.

4. c) Construct validity:
In construct validity the investigator in
concerned with the question. Is the concept under
investigation being adequately measured? Is there a
valid basis for inferring the score? Evidence of
construct validity is not established with in a single
study.

5. 2.Reliability:
Refers to the accuracy and consistency of a
measuring tool. A mesure is reliable when an individual
remains nearly the same in repeated measurements.
Reliability is measured by reliability coefficient.
3.Sensitivity and appropriateness:
Sensitivity refers to the capability to detect changes
or difference when they to occur. Multy model
measurements are made because of variation in
sensitivity.

6. If a measure is in appropriateness, it could measure
wrongly.
4.Objectivity:
Objectivity means freedom from bias. A test should
yield a clear score value of each performance.
5.Economy:
Test can be given in short period of time
6.Practicability:
Simplicity of administration, scoring and
interpretations are important factors in selecting a test.

7. 7.Interest:
Both the researcher and the subject should enjoy
the experience of data collection.

9.  OBSERVATION:
Observation is one of the basic and oldest research
method to gather data. It is a two part process i.e, 1)
someone to observe observer and 2) there is
something to observe the observed.
characteristics of observation
 It is both physical & mental activity.
 Observation is selective.
 Purposive and not casual.

10. T YPES OF OBSERVATION:
 Participant observation
In this, the observer is a part of phenomenon
or group which is observed and he acts as both
an observer and participant.
 Non-participant observation
In this method, the observer stands apart
and does not participate in the phenomenon.
Observation in unnoticed manner.

11.  Direct observation
Observation of an event personally by the observer
when it take place.
 Indirect observation
Mechanical observation
 Controlled observation
It is carried out in the lab or field. It has pre-planning.
 Uncontrolled observation

12. OBSERVATION TOOLS AND RECORDING
DEVICES
1. Schedule
2. Field observation log
3. Mechanical devices

13. INTERVIEW
It is an organized conversation with the client to
obtain client history.
Types of interview:
. Face-face interview
. Telephone interview
. Computer Assisted Personal Interview

14.  PHASES OF INTERVIEW
Orientation phase:
Introduce ourself and maintain IPR
Working phase:
Gather the information
Termination phase:
Coming to an end

15.  INTERVIEWING PROCESS
o Preparation:
planning, list of name, address, location, trained
person, implementation, hard working, don’t deviate
from the topic, friendly, unbiased and timing.
o Introduction
Investigator is a stranger to the respondents.
o Developing rapport
o Carrying the interview forward

16. o Recording the interview
To avoid lose of data
o Closing the interview