Lecture 10

追加: 2026-05-06

[00:00:15]Ladies and gentlemen, this is the 10th lecture of this course and in this lecture we are going to discuss the examples of the randomized control trials. In the previous lecture, we discussed in detail what a randomized control trial is and what are the steps to conduct a randomized control trial.

[00:00:40]In this lecture, in this lecture, I am going to discuss some of the examples of randomized control trials with you so that it must be very clear in our minds that how it is done.

[00:00:58]The first example that we take is the case study insecticide treated bed nets.

[00:01:12]A study in western Kenya use RCTs to assess how prices affected the use of insecticide treated pment.

[00:01:26]We in some of the countries in our countries we cannot visualize the situation in some of the other countries but since it is their problem they the insecticide insecticide treated bed nets are to be used there over there for their health reasons and this is why a a study to through RCT to assess says how prices affected the use of insecticide treated by Kenya western Kenya.

[00:02:04]So 20 similar health centers were randomly assigned to four treatment groups offering the insecticide treated bed nets at different prices.

[00:02:21]So there are 20 similar health centers and randomly assigned to four treatment groups offering these beds at bed nets at different prices.

[00:02:39]The control group did not offer IETS that is insecticide treated bed nets.

[00:02:49]The RCT, the random control trial showed that when clinics asked for a small level of payments, the demand for these treated bed nets, insecticide treated bed nets decreased.

[00:03:10]But the data also showed that those who paid more for the nets did not use them any more often than those who paid less or nothing at all.

[00:03:27]What the data shows that those who those who paid more for the nets did not use them any more often than those who paid less or nothing at all.

[00:03:38]So the findings of the study were used to support the argument for free or subsidized insecticide treated bed nets distribution.

[00:03:54]The second case study is the cash incentives for triple handing.

[00:04:03]A project in Zambia supported an NGO namely shared values Africa aimed to look to look at the factors that determine how climate smart agricultural technologies are adopted by small world farmers in developing countries.

[00:04:31]So the aim is to to look at the factors that determine how climate is smart agricultural technologies are adopted by small old farmers in developing countries those having small level of fields small smaller fields. So the project identified a cause relationships between input costs, incentives and farmer characteristics on one hand and outcomes including these survival rates program.

[00:05:17]On the other, the project found clear evidence that subsidizing adoption and providing cash incentives for sustained efforts on land use chain has a positive impact on tree survival permits. So this is an important finding that there is clear evidence that if the adoption the subsidization is adopted and there is provision for cash incentives for sustained efforts on land use change. It has a positive impact on the tree survival rates.

[00:06:03]Then the next study is the primary schools in Kenya.

[00:06:11]There are two types of schools in Kenya.

[00:06:19]those hired by the government, the rather the school teachers in Kenya who have been hired by the government, they pay handsome salary and they have all the securities of a government employment.

[00:06:40]Next those hired locally by parent teacher associations that is PTAs.

[00:06:49]The government high teachers are protected and receive a much higher salary compared to the PTA hired teachers that we know in our country also that the government had teachers are protected and receive a much higher salary as compared to those teachers who have been hired by the parents teacher association.

[00:07:16]So in this experiment in Kenya, the parents teacher associations were funded to hire qualified graduates of teacher training colleges as extra contact teachers for two years. In addition to because there are government teachers now the PTA has been given authority and funding to hire the qualified teachers as extra contact teachers for two years.

[00:07:51]However, these contract teachers who were hired by the PTAs were to be paid only about a quarter of the salary of government teachers.

[00:08:05]reviewed and their contracts would be renewed after one year once the PTA approves it. So their conditions are stringent.

[00:08:22]They are paid less salary also and their contracts have to be re renewed every year and the PTA has to approve their approve their reappoint their reimployment.

[00:08:47]So however the contract teachers followed the same curriculum as government teachers and were assigned to teach a fixed group of first grade students. So curriculum is same as being taught by the government teachers, government of partner teachers.

[00:09:14]But these contract teachers teach the same curriculum to a fixed group of first grade students.

[00:09:24]What were the findings?

[00:09:27]First, providing a school parent teacher association with funds to hire extra contact teachers to improve learning.

[00:09:40]Next, the scores of students in such schools were 0.2 to a standard deviations higher than those of students in control schools.

[00:09:55]Moreover, students who were exclusively assigned to contract teachers enjoyed a 0.29 standard deviation gain in the schools while those under government teachers report. Second, in schools with only government teachers, the bunking rate was 42%.

[00:10:19]In contrast, the contract teachers were 20% more likely to be teaching during random visits and this is why as a result their students learned more. Moreover, the government teachers in schools with contract teachers decreased their own effort.

[00:10:46]So the probability that they would be found in class teaching during a random visit decreased by 27%.

[00:10:55]And of course therefore their student did not gain significant income.

[00:11:01]So this suggests that instead of dealing with the teaching problem by appointing more government teachers, it is better to empower parents bodies to appoint capable contract teachers.

[00:11:18]So it is less expensive and more effective.

[00:11:23]There can be two opinions or the in the policy making of such kind of findings but there is no doubt that these findings are very important and of course crucial as the teaching schools is very important for the development of society. So this finding is also very significant and which has been studied through the use of randomized control trials.

[00:12:06]Then the immunization in Jaipur, Jaipur, Rajasthan.

[00:12:22]The study is about immunization in a tribal area.

[00:12:31]Immunization is done as a preventive to check the various kind of diseases.

[00:12:42]We all had immunization.

[00:12:46]So this is about a study of immunization in a tribal area.

[00:12:56]It is a fact that the immunization has been abysmally low in tribal with the high absentism prevalent among government health staff and poor families being averse to taking their children to health centers to complete a fullphase immunization program. This remains painful.

[00:13:24]The poor families, the tribal families, they are not very much interested in taking their children to health centers to complete the full course of the immunization program.

[00:13:39]So an randomized control trial was utilized to study the impact of imunization in a tribal area of Udaur in Rajasthan.

[00:14:01]The steps are as follows.

[00:14:08]The study divided villages into three groups.

[00:14:14]Number one, control group of villages.

[00:14:18]Second, a second terming these as a villages which were served by a mobile demonization team arriving at fixed days and times in different villages.

[00:14:35]And third there can there in the third we can we term these villages as e villages. Here in addition to mobile teams each immunization was rewarded with a kilogram of lentils.

[00:14:55]Further after all the five immunizations they were rewarded with a set of thalies.

[00:15:02]So here the we see that there is more than one intervention.

[00:15:09]The first in intervention is in the group a villages where who are served by a mobile demonization which arrives in the village in fixed days and times.

[00:15:27]Whereas the next we term these villages we have termed these villages as B villages.

[00:15:35]Here in addition to the mobile teams the mobile teams also come. However there is reward also for humanization.

[00:15:45]Each humanization is rewarded with a or was rewarded with a kilogram of 1 kilogram of lentils. Further after all the five imunizations they were rewarded with with a set of thalies a kind of intensive what were the findings the findings were that in the control group only 6.2% 2% of kids in the age group one three of years were fully im immunized control group where there is no intervention and no facility of the mobile or the award which was less as it used to be earlier that they will go to the health center for getting the immunization. So in the control group only 6.2% of kids in the age group 1 to three of years were fully immunized.

[00:16:55]Whereas in intervention A villages 16.6% 6% of kids in the age group of 1 to 3 years were fully immunized and in the intervention B villages 38.3% of kids in the age group of 1 to 3 years were fully immunized. So we we have the differences very large difference control group only 60 to 6.2%.

[00:17:35]Whereas in intervention a villages where mobile teams go for the immunization the the the kids immunization rate is 16.6%.

[00:17:49]Whereas in the intervention villages where there is mobile also and the award also the 38.3% of kids in the same group were age group were fully immortalized. So we have ourself the difference.

[00:18:06]So also children from the villages neighboring the B villages were more likely to be fully humanized immunized than others which is suggested that the news of efficient immunization plus incentives traveled from one village to the other. Further as immunizations were more regular in the cluster B villages the cost per fully vaccinated child was lower than elsewhere.

[00:18:39]So this study we find here the the importance of the study and third.

[00:18:53]So we have observed by these examples how RCTs have been successful not only in medical sciences but also in the development economics or in the in the social in in in in the in in the economic social development or in education. They have been able to to give a very important results through the RCTs. These randomized controls are now frequently utilized.

[00:19:40]Of course, they were frequently utilized in the medical sciences or the health sciences. In fact, it became from there only. But now it is being utilized fully in the in the economics or developmental economics also.

[00:20:04]So that is the use of it. My own interest from this to this RCT they started when professor Aiji Dunag Benji from the Harvard University he was awarded the Nobel Prize.

[00:20:26]He works for the poverty lab in Harvard University and he has experimented this in the in West Bengal by using the RCT.

[00:20:45]So that time the controversy started that whether our cities should be utilized for economic studies or for the development studies and since I had a very personal relation with professor Benerji as he was my immediate senior in MA at the center for economic studies and planning while doing MA. He was my senior and he was bright from very beginning. So we used to consult him regularly to sir and he also used to help us very gladly. So I was since I had a very personal say emotional relation with him. So I then started working on the RCT and then I found out these RCTs are of very importance, very crucial and then there were various articles that came up in support of the RCTs on the randomized control trials to be utilized.

[00:22:21]in the developmental studies also.

[00:22:26]So it I got interested into it and I started going through the literature on the randomized control tri. So the that is the that is the that is why I became interested in RCTs and then I finally found that this is a very latest modern and a state ofthe-art tool to study the results of various interventions maybe in the health or medical sciences.

[00:23:09]or in the developmental studies. So now we shall be discussing the strength and weaknesses of the randomized control trials. So what are these randomized control trials? These randomized control trials are considered the gold standard for studying cause effect relationships.

[00:23:36]It has following advantage.

[00:23:40]Good randomization reduces any population loss that we have observed. Blinding or masking is easier to conduct in RCT than in observational studies.

[00:23:56]In this process, those involved in the study, eg participants, data collectors, data analyst, etc. are not aware of the kind of intervention each participant receives.

[00:24:14]This method used to reduce observer bias also since the researcher may already have initial expectations of the effect of intervention and it happens it naturally comes into it. So the RCT reduces the observer pass also.

[00:24:36]Then as the bias is minimized, the RCT has high internal validity.

[00:24:45]Meaning that the observed difference between the experimental and control groups are due to the intervention not from the factors.

[00:24:56]This is the very high internal validity.

[00:25:01]The differences between the experimental and group control groups that have been observed are only due to the intervention and not from other factors.

[00:25:14]That is one of the strengths.

[00:25:17]Information regarding the participating individuals is clearly identified and recorded despite the strength of RCT.

[00:25:32]It also has some limitations and may not always be suitable for all scenarios because of course as we have seen in the developmental studies, in the health studies, in the medicinal studies, this is very effective. However, it is not necessary that it is effective and suitable for all scenarios.

[00:26:03]We come to the to its disadvantages.

[00:26:08]Some of its disadvantages include the follow.

[00:26:16]RCTs are time initiative, intensive and expensive. Naturally the it takes longer time also and it has more it requires more budget also.

[00:26:32]And what we find nowadays that the time given to the researchers for any project is being reduced and also the the budget that they receive is also being reduced.

[00:26:47]So in these scenarios when time is being curtailed and budget is being curtailed our cities are not to be very attractive.

[00:27:00]Some of these may take many years to complete and even the collected data may not be enough to assess the effect of the treatment.

[00:27:12]Then the chosen population may not be representative of the whole.

[00:27:25]Even if the results showed that the inter intervention positively affected the participants, this may not be true for the general population.

[00:27:34]So the population of the patients or the population of the beneficiaries which has been chosen to study may not be representative of the hall.

[00:27:54]population and this why even if the results show and that the intervention was positive has positively affected the participants.

[00:28:11]This may not be generalized for the whole of the population and and this may be wrong to generalize for whole of the population.

[00:28:24]Further some participants may have been lost in the followup stage.

[00:28:32]There are instances when participants actively participating in the trial drop out looking forward.

[00:28:43]So if those on whom we are studying and the participants those who are participating if they drop out during the followup exercise then this would affect our result and a high percentage of lost participants and data may lead to inaccurate results.

[00:29:15]So given the strength and weaknesses of randomized controls, we know its benefits no doubt but we have various limitations financial time and human resource.

[00:29:38]So if a researcher wants to employ this randomized control trials in his or her study then he must decide it on the basis of availability of time, availability of budget and the availability of the type of participants. friends those who will be regular drop drop out.

[00:30:13]So if the if our criteria fulfills then we can always opt for the for the RCTs and if suppose we have low budget, we have less time and we do not have dependable participants then it is better to adopt out to the traditional methods.

[00:30:46]Whereas if we have these facilities, if we have enough time, if we have enough budget and we we have the the participants who are also committed for this study, then we can always choose the option of randomized control trials.

[00:31:06]So ladies and gentlemen, I am I am very hopeful that I have been able to clear by giving these these examples how this randomized control trials are important for the research studies.

[00:31:27]I have given the references and of course as I recommend you can have other references also for your your extensive study. Thank you very much.