Shadowing Practice: Sequential, Multiple Assignment, Randomized Trial Designs With Dr Kidwell - Learn English Speaking with Video
Les maken...
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Hello, and welcome to JAMA Evidence, our podcast series based on core issues in evidence -based medicine.
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Today, we will be discussing sequential, multiple assignment, randomized trial designs.
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I'm your host, Dr. Roger Lewis, statistical editor for JAMA and co -editor of the JAMA Guide to Statistics and Methods series.
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I'm here with Dr. Kelly Kidwell.
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Dr. Kidwell, thank you so much for joining us.
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Can you go ahead and tell our listeners a little bit about yourself?
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Sure.
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Thank you so much for having me, Roger.
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I'm Kelly Kidwell.
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I'm a professor of biostatistics at the University of Michigan School of Public Health, and my expertise is in clinical trial design and analysis,
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and in particular, the sequential multiple assignment randomized trials or SMART design.
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Well, again, thank you so much for joining us.
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So the name of this approach to a trial design is a bit daunting, so let's try to break it up a little bit.
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So for each of those terms, can you go ahead and tell us what it means and then how we put it together in designing a clinical trial?
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I completely agree with you that the vocabulary around smart design is quite daunting.
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So what an excellent first question to start with.
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So sequential is about a few things.
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One is that we're interested in sequences of treatments.
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And in this clinical trial design, we're going to have sequential randomization.
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So those terms aren't next to each other, but that's really what's happening and defines this trial,
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such that at least some group of participants will be randomized twice in sequence.
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So usually there's some upfront randomization
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and then a subsequent randomization for some group of participants based on their response to the initial treatment.
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And so that multiple assignment comes into the fact that we'll have this sequential treatment assignment.
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So individuals could be assigned to multiple treatments.
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And this is all wrapped up in a clinical trial.
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So we're going to use this SMART clinical trial tool to give us robust evidence for sequences of treatments
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that adapt to individual responses or patient status.
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So in contrast, in a traditional or a simpler clinical trial design.
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We just randomize once, and then the patient either does well
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or perhaps doesn't do so well on the treatment to which they are assigned.
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And if they don't do well, we often have some sort of rescue therapy or they have to leave the trial.
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So how is the experience of a patient or a participant different in a SMART design?
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Right.
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So in a general, standard, traditional randomized clinical trial, we're really looking at one point in time,
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sort of this trial in a vacuum.
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The SMART is going to say, let's look at that patient over the course of care.
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So in a standard trial where you might stop collecting their data and treating them off trial if they didn't respond, we actually want to use that data.
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And in fact, we might want to randomize the treatment to
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which rescue therapy they're getting so that we can collect unbiased evidence
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and use causal inference to better understand what the effect of that treatment is.
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And not just that treatment, but the entire treatment sequence.
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And so really for the patient,
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it might not be too different than a standard trial because we're going to treat you over the course of your care.
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But to the investigators, we're going to make sure that
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that data is collected for our trial and there might be randomization for the treatment assignment that follows for that patient.
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So, let's think a little bit about how we analyze or what we can learn from those two different approaches.
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So in the first, we randomize at a single point in time, and if the patient doesn't do well,
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they either drop out of the trial or we assign a rescue therapy.
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Whereas in the SMART design, if they require a change in therapy, we actually randomize what we do.
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So what's different about what we can learn from those two different approaches?
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That's right.
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Often in our standard clinical trial, in that one stage where the patient drops out or receives clinician or patient choice therapy,
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we no longer make inference or have any decisions or really robust results about that subsequent treatment or their outcome.
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Whereas in the SMART, by randomizing that individual and continuing to collect that data,
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we will be able to have really robust evidence over the course of care, over the sequence of treatments
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that could have adapted based on their response to allow us
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to give these sequential guidelines to clinicians to treat the patient not just up front at one point in time,
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but over time, and really tailor it to how they're doing, if they responded, if they adhered, if they engaged with that treatment.
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So in a sense, this more closely follows what happens in actual clinical care,
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where we make a series of treatment decisions based on the patient's prior response, but in this case, you're setting it up
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so we can rigorously learn about what is the best next
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thing to do based on what's happened to the patient so far.
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Is that a fair summary?
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Absolutely.
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We are looking at a type of clinical trial that more closely mimics the way in which treatment is practiced.
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And so that we can provide evidence for these treatment strategies
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that adapt to individual's response or patient status in the way that we would actually treat them in practice.
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Let's suppose that a SMART design is run and there's two points at which patients are randomized,
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maybe the initial therapy and then after some defined period of follow -up.
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What does the result look like in the publication that results,
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and how can clinicians utilize the results of the SMART in guiding their own clinical care?
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One of the amazing advantages of a SMART design is
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that it can answer many questions as opposed to just what is the best treatment at one time.
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We can think about what is the best treatment to begin with?
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What is the best subsequent treatment for those who respond?
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What is the best subsequent treatment for those who don't respond?
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And then we can think about that entire sequence of, okay, so what do we start with?
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How do we change?
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When do we change?
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For whom do we change and what treatment do we give them?
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And so we can really get from SMARTS this sequence of treatments adapted to patient response.
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Not only that, we can collect baseline information, so information up front at the start of the trial, and information about the patient and how they're doing with the treatment,
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how they're adhering, how they're engaging, if they're having side effects,
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and use that information to better tailor the treatment assignment to that individual so that after the trial, right, we have all this information.
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And we can look at what are the best sequences of treatments for which particular individuals.
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The fact that the SMART design more closely matches actual clinical care,
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which the sequences of therapies we offer patients is informed by their responses to prior therapies is an obvious advantage.
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But what are some of the limitations or challenges in either the implementation or the interpretation of a SMART clinical trial?
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I think there are a few limitations and also just lack of knowledge of this design and its opportunities that it offers.
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Some of the limitations are that individuals think, oh, now that we have multiple randomizations or multiple assignments in sequence,
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this is now logistically infeasible, or you're going to lose more people if you have to consent multiple times.
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So one thing is that we often just consent once at the beginning of the smart design.
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and we may randomize multiple times.
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Alternatively, you could randomize up front to that sequence that they may follow, whether they respond or do not respond.
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So logistically, this doesn't have to be very difficult.
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We also have lots of technology that helps us with complex trials, if you want to say that it's complex, although it's not.
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Number two is that individuals are worried about bias coming into play from a smart design
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because of these multiple randomizations and the subsequent randomization depending upon patient response or status.
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This is not a concern because we do not compare these treatment pathways or you first get A,
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you respond and you continue versus you first get A, you do not respond and you switch to B.
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We're not going to compare those people.
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We know that they're different.
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One responded and one didn't, and we can have some issues if we do those comparisons.
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We're looking at what we call adaptive interventions or dynamic treatment regimens that include that entire treatment sequence that's adapted.
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So start with A, and if you respond, continue.
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And if you don't, receive B.
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We're going to think about what are the effects of that entire sequence that's tailored to the response.
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Another misconception is that a SMART is an adaptive design.
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Usually a SMART is a fixed design, not an adaptive design, meaning
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that we're not going to use information from patients who have
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been through the trial to change the trial in some way for future patients.
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So we're not going to change randomization probabilities or eligibility criteria based on the information we've gained from the trial thus far.
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What does happen in a SMART is that patients' treatment might change based on their own response.
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So there might be a within -person adaptation, but there's no between -person adaptation.
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And so generally, these aren't adaptive designs.
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Since we're trying to learn more from a clinical trial that's a smart design versus a traditional design
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that just has a single point of randomization, it seems like we might need larger sample sizes to answer the additional questions.
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What are the challenges, if any, with respect to sample size requirements for a smart design?
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If you see pictures of smart designs, they look a little bit intimidating because there's a fair amount of branching that occurs due to these sequential randomizations.
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And often investigators are quite worried that we're going to require thousands of patients.
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The thing is that to size a SMART is just like sizing any other trial.
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And so it's really dependent on the primary aim, which can be similar to a standard one -stage trial and compare,
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for example, the initial treatments.
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Alternatively, the aim can be based on those embedded tailored sequences of treatments or the adaptive interventions.
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And for those perhaps more patients may be required than a standard trial.
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However, this really isn't an apples -to -apples comparison of a SMART design to a standard or traditional one -stage trial.
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As I mentioned before, the questions
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that we can answer in a SMART are much different and many more than we could with a standard design.
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And so perhaps we may need more depending on the primary aim, but we're going to get a lot more information,
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data, robust results, and more practical information that we can use after a smart design.
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In your article, you discuss a study that was performed by Fortney et al that used a smart approach.
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Can you tell us a little bit about what they did, what they found, and how they analyzed their data?
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Sure.
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So in this study, they had a design where individuals were sequentially randomized to better understand some effects of direct
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and indirect telecare.
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And what they did is they answered questions that are sort of more similar to one stage design.
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So they said, okay, so what's the best first thing to start with?
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And then subsequently, what do we do if individuals aren't responding well to that initial treatment or intervention.
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So they haven't yet pieced together that full sequence.
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It seems like that's subsequent analyses for this group in terms of figuring out,
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so what is the best overall sequences of treatment that can adapt to the individuals?
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While they answered those individually, what they could find when they move forward with the analysis of the adaptive intervention is
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that there might be interactions between the initial treatment
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and the subsequent treatment for
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which we can only really quantify in these types of SMART designs as opposed to individual randomized clinical trials.
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And so what they likely will subsequently do is look at
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that sequence of treatment over the course of the trial
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or those adaptive interventions to see if there are any interactions between the first step and the second step.
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I'm Roger Lewis, and I've been speaking with Professor Kelly Kidwell about sequential multiple assignment randomized trials.
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You can find a link to her article in this episode's description.
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This episode was produced by Daniel Musisi at the JAMA Network.
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To follow this and other JAMA Network podcasts, please visit us online at jamanetworkaudio .com.
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Thanks for listening.
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Woordenschat en spreektips bij deze les
Deze spreekles is gebaseerd op de video “Sequential, Multiple Assignment, Randomized Trial Designs With Dr Kidwell”. Deze woorden komen het vaakst terug: treatment, trial, design, smart, patient. Deze video bevat 103 zinnen en 2153 woorden om na te spreken. Het gesproken deel duurt 13:26. De spreker praat in een natuurlijk tempo van ongeveer 160 woorden per minuut, dicht bij een alledaags gesprek. 84% van de woorden hoort bij de 3.000 meest gebruikte Engelse woorden; de rest kun je beter vooraf bekijken. 18 van de 103 zinnen zijn vragen, dus het is goede oefening voor vraagintonatie en korte antwoorden.
Belangrijke woorden in deze video
15 woorden uit de video die het leren waard zijn, met uitspraak en betekenis:
| Woord | Uitspraak | Betekenis |
|---|---|---|
| sequence zelfstandig naamwoord | /ˈsiː.kwəns/ | volgorde, reeks |
| assignment zelfstandig naamwoord | /əˈsaɪn.mənt/ | toewijzing, toekenning |
| subsequent bijvoeglijk naamwoord | /ˈsʌbsɪkwənt/ | volgend, daaropvolgend |
| adaptive bijvoeglijk naamwoord | /əˈdæp.tɪv/ | adaptief |
| adapt werkwoord | /əˈdæpt/ | aanpassen |
| collect werkwoord | /ˈkɑlɪkt/ | verzamelen, opstapelen |
| intervention zelfstandig naamwoord | /ɪntɚˈvɛnʃən/ | tussenkomst |
| robust bijvoeglijk naamwoord | /ɹəʊˈbʌst/ | robuust, degelijk |
| tailor zelfstandig naamwoord | /ˈteɪlɚ/ | kleermaker, kleermaakster |
| rescue werkwoord | /ˈɹɛs.kjuː/ | bevrijden, redden |
| compare werkwoord | /kəmˈpɛɚ/ | vergelijken |
| participant zelfstandig naamwoord | /pɑːɹˈtɪsəpənt/ | deelnemer, participant |
| limitation zelfstandig naamwoord | /lɪmɪˈteɪʃən/ | begrenzing, beperking |
| assign werkwoord | /əˈsaɪn/ | toewijzen |
| whereas | /(h)wɛɹˈæz/ | hoewel, terwijl |
Phrasal verbs die je zult horen
| Woord | Betekenis |
|---|---|
| figure out werkwoord | uitvogelen, er achter komen |
Zinnen om te herhalen
Korte, volledige zinnen uit de video die je in alledaagse gesprekken kunt gebruiken:
- Let's try to break it up a little bit.
- One is that we're interested in sequences of treatments.
- We can think about what is the best treatment to begin with?
- How do we change?
- When do we change?
Grammatica in deze video
De structuren die de spreker het meest gebruikt, met de exacte woorden uit de video:
| Structuur | In de video |
|---|---|
| Lijdende vorm be + voltooid deelwoord — het gaat om wat er gebeurt, niet om wie het doet | will be randomized · could be assigned · are assigned |
| Betrekkelijke bijzinnen who / which + zin — extra informatie over een persoon of ding | those who respond · those who don · aim, which can |
Uitspraak om op te letten
De spreker gebruikt 44 samentrekkingen en verkorte vormen, zoals we're, they're, I'm. Spreek ze kort uit, zoals je ze hoort.
- De klanken “sh” en “zh”: intervention /ɪntɚˈvɛnʃən/, limitation /lɪmɪˈteɪʃən/, interaction /ˌɪn.təˈɹæk.ʃən/, adaptation /ˌæd.æpˈteɪ.ʃən/, contrast /kənˈt(ʃ)ɹæst/
- Lange woorden — let op de klemtoon: intervention /ɪntɚˈvɛnʃən/, participant /pɑːɹˈtɪsəpənt/, limitation /lɪmɪˈteɪʃən/, interaction /ˌɪn.təˈɹæk.ʃən/, subsequently /ˈsʌb.sɪ.kwənt.li/
Klanken die Nederlandstaligen lastig vinden:
- Stemhebbende eindmedeklinker — /b/, /d/, /g/, /z/, /v/ niet verscherpen: adaptive /əˈdæp.tɪv/, whereas /(h)wɛɹˈæz/, engage /ɪnˈɡeɪd͡ʒ/, depend /dɪˈpɛnd/, oppose /əˈpoʊz/
- /æ/ — opener dan de Nederlandse “e”: adaptive /əˈdæp.tɪv/, adapt /əˈdæpt/, whereas /(h)wɛɹˈæz/, interaction /ˌɪn.təˈɹæk.ʃən/, podcast /ˈpɑdˌkæst/
- /g/ — een harde plofklank, geen Nederlandse “g”: engage /ɪnˈɡeɪd͡ʒ/, investigator /ɪnˈvɛs.tɪˌɡeɪ̯.təː/, guideline /ˈɡaɪdˌlaɪn/
Zo oefen je met deze video
- Luister de hele video één keer zonder te spreken en noteer de woorden die je niet kent.
- Begin op 0,75× snelheid, spreek zin voor zin na en ga terug naar normale snelheid zodra het makkelijk gaat.
- Neem jezelf op en vergelijk met het origineel; let daarbij op woorden als sequence, assignment, subsequent.
Wat is de Shadowing-techniek?
Shadowing is een wetenschappelijk onderbouwde taalleermethode die oorspronkelijk is ontwikkeld voor professionele tolkentraining en gepopulariseerd door polyglot Dr. Alexander Arguelles. De methode is eenvoudig maar krachtig: je luistert naar native Engelse audio en herhaalt het onmiddellijk hardop — als een schaduw die de spreker volgt met slechts 1–2 seconden vertraging. In tegenstelling tot passief luisteren of grammaticadrills, dwingt shadowing je hersenen en mondspieren om echte spraakpatronen tegelijkertijd te verwerken en te reproduceren. Onderzoek toont aan dat het de uitspraaknauwkeurigheid, intonatie, ritme, verbonden spraak, luisterbegrip en spreekvaardigheid aanzienlijk verbetert — waardoor het een van de meest effectieve methoden is voor IELTS Speaking-voorbereiding en echte Engelse communicatie.