Estrategias de enseñanza – aprendizaje con las TIC

If the IPPT is to be used outside the research situation it is necessary that it meet certain psychological criteria (McCauley and Swisher 1984, Sumner 1987, Davies 1990, Kline 1986, Harris 1990). As indicated above some of these have been met fully, some partially and others still require to be undertaken.

The scientific development has included cultural adaptation, item analysis, standardisation and estab­ lishment of norms for three socioeconomic groups. Other psychometric studies included inter-rater reli­ ability, test-retest reliability, face, content and construct validity.

Item Analysis :

Each item for noun labels and each situation for questions in the IPPT was carefully deliberated and piloted. Items familiar to children of all social groups were further considered. Item analysis refined the process of final selection. It included the use of item difficulty analysis that discarded uniformly difficult or easy items. It also defined items suitable for a particular age group based on their level of difficulty. The process of item discrimination was applied to evaluate an item’s ability to distinguish language perfor­ mance in test subjects. Item bias examined presence of significantly different performance on a given item by children from each socioeconomic class. These statistical procedures promote the reliability and validity of the IPPT.

The mean and standard deviation of raw scores in six sectors has been reported and analysed for each of the socioeconomic groups .

Sample size

The Indian Picture Puzzle Test has been standardised on 616 children to construct norms, as percentile charts, for three socioeconomic groups. When individual SES groups are considered the sample size conforms to the WHO recommendations i.e. 200 in each group (WHO 1986).

The ideal sample size for use of the total population norms is 1300 (WHO 1986); however, the gross differences between the groups makes this usage inappropriate.

Description of the normative sample :

The Kota sample was clearly defined in terms of geographic location, socioeconomic status and home background.

Reliability studies :

Ideally reliability studies should be carried out on approximately 10 per cent of the sample population (Glascoe et al 1990). The acceptable correlation coefficients for reliability studies recommended by dif­ ferent authors range from 0.7 (Harris 1990), 0.8 (Glascoe et al 1990) to 0.9 or better (Salvia and Ysseldyke 1981).

Inter-rater reliability was carried out on 52 (10%) response sheets; coefficients ranged from 0.99 to 0.97 in the language sectors of the IPPT. Variation consequent to different examiners or different record­ ers has not yet been undertaken.

Test-retest reliability was carried out on 23 (5%) subjects; coefficients were between 0.93 and 0.95 in the language sections. The test-retest reliability is slightly lower for the sections entitled Orientation of the piece and Expressive response to questions (0.763 and 0.748 respectively). The former may reflect the rather arbitrary method of evaluating how a child orientates a piece to its recess (refer p....). The latter is of greater concern, and probably reflects a number of factors influencing the child - e.g., level of relax­ ation/rapport; practice effect'; variability in the amount children talk on separate occasions.

The psychometric status of the IPPT would be strengthened by a study of inter-examiner reliabil­ ity and a bigger sample for test-retest reliability.

Validity :

Non-empiricai

extensively used in the U.K. The IPPT also achieves face validity judging by the responsiveness shown by the children, parents and field workers to the test.

The content validity of the IPPT is supported by the use of pictures to test both vocabulary and the level of expressive language in well established tests, for example, the Reynell Developmental Language Scales (1969), the British Ability Scales (Elliott et al 1978) and the British Vocabulary Test (Dunn et al 1982). Similarly the use of form boards to explore spatial skills has been established for over half a century, for example, the Seguin Form Board in the Merrill-Palmer Preschool Performance Test (1931- 48) and the Stanford Binet Test (Terman and Merrill 1960).

The additional field studies I and II (p. 136 - 139) enhance construct and content validity. They explored the psychological processes underlying the IPPT and thus what it purported to test. In the first field study the children named more miniature toys than pictures of the verbal labels of the IPPT. This indicates that the verbal labels were in the children’s lexicon and suggests that immature ability to interpret two- dimensional pictures had constrained naming. In the second field study advantaged adults were able to name all the pictures and situations illustrated, implying that the picture in the IPPT was not ambiguous. Therefore, the constructs of the IPPT were clarified and indicated that ability to perceive pictures was measured by the test. The third field study in a rural village, (p. 154 ) although on a small sample using index children as their own controls implied benefit from an intervention programme embodying the abilities of the IPPT. This lends a modicum of treatment validity to the IPPT. Further, more scientifically designed treatment validity studies are indicated.

Empirical;

Neither concurrent validity nor predictive validity have yet been undertaken for the IPPT. It is essential that the external criterion has itself been validated and standardised. In the current status of test standardisation in India (Murlidharan 1992) it is difficult to identify a suitable test. Also, most rural and slum children do not attend nursery schools and a teacher’s judgment on their abilities cannot be used as an external criterion to derive concurrent or predictive validity. Establishing predictive validity for an ability which is sensitive to environment stimulation like language, may pose difficulty as persisting deprivation may depress the ability with time.

If in the future the test is modified for surveillance Sensitivity and specificity indices, yield and predictive value will need to be derived to assess the productivity of the test as a screening tool.