Book Review: Delta’s Key to the TOEFL iBT, Advanced Skill Practice

(NOTE: The TOEFL books that Magoosh reviews and recommends reflect the older, pre-August 2019 version of the test. As of this writing, there are no TOEFL prep books that reflect the newest version of the test. Fortunately, older-format books are still very useful in prepping for the current TOEFL. For details on this, see Magoosh’s tutorial on using older prep for the 2019 TOEFL.)

51OVMi5cq4LAlthough I have used practice material from Delta’s book of seven practice tests in classes before, I haven’t used it much, and I’d never used Delta’s Advanced Skill Practice before buying it for this review. So when I started going through this book and saw how much material it includes for such a low price, I thought, “I wish I’d known about this book sooner!” And then the glow faded as I spent more and more time looking at the material. To put it simply, Delta’s practice material doesn’t accurately mimic the real TOEFL and the challenges it presents. Having a lot of practice material doesn’t mean it’s a good book. The quality of the material is much more important. So, similar to Barron’s TOEFL book, Delta may be tempting, but I don’t recommend it for self study.

It could be very convenient for a teacher or tutor to draw from for extra practice material—the organization, price, and straightforwardness of the exercises make for very easy use—but then again, McDonald’s is convenient too. And I wouldn’t serve McDonald’s to my students if they were trying to improve their health.

Quality of practice material

Okay, so the quality of Delta’s practice material isn’t as low as the quality of McDonalds’ food. (You can probably tell I’m not a fan of fast food…) That may have been a little too harsh, because there are definitely worse options available. Delta more accurately represents what TOEFL reading passages look like than Barron’s does, for example. But it’s still full of small problems that really add up to a much larger quality issue.

Let’s start with the biggest problem: length. In the sections for reading and listening practice, the texts and recordings are all too short. This is not accidental, I’m sure. I imagine that the author, Nancy Gallagher, consciously wrote short and fast exercises with just a few questions each. After all, shorter exercises are easier to incorporate into a class—the teacher has more freedom to use fewer or more questions. But by doing that, the Gallagher completely removed TOEFL timing from that practice, and timing is one of the biggest challenges of real TOEFL reading. Similarly, note-taking and memory, two of things that make TOEFL listening difficult, are almost completely irrelevant for those shorter recordings. Listening to a two-minute lecture then answering two questions is not the same as listening to a five-minute lecture and answering six questions. When the recordings are short, you don’t need notes. On the real TOEFL, you definitely need notes, and your preparation should help develop that skill.

There are some full-length practice sets in the four practice tests, but those aren’t perfect, either. The difficulty of the questions doesn’t match the real TOEFL, for one. The wrong answers to reading questions aren’t tricky enough, because they’re too often irrelevant to the text. That type of wrong answer can be difficult for the listening questions, but less so for the reading, because it’s easy to go back to the text and compare wrong answer choices to it. If a topic is mentioned nowhere in the text, it’s easy to eliminate. (In listening, it’s harder because you have to rely only on memory and notes.) At the same time, the right answers often use nearly the exact same words as what’s in the text. The easiest of TOEFL reading questions do that, but it’s rare. On the real test, the information from the text is paraphrased in the right answer, using synonyms and different sentence structures, not plainly copied.

And although some of the questions are more challenging, they’re made hard in the wrong ways. They might not give you the paragraph number, for example, so you have to search through the whole text. In an actual TOEFL, you always know which paragraph to look at, because it is provided next to the question.

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It’s not just the questions; the texts and recordings also have their flaws. The recordings don’t include much natural language, for instance. Actors say “going to” instead of “gonna,” they don’t pause, and they don’t repeat themselves like they do on the real TOEFL. And the quality of the actors is varied. Some sound like actual people talking, but others sound like they are speed-reading through a script. In at least one recording, an actor that should be a part of a conversation is instead giving a monologue (speaking alone). And a text the tells about the cycle of the moon? That’s not like the TOEFL at all—texts should be about relatively unknown, academic topics, not common knowledge.

Even the format suffers. Since 2011, the TOEFL has given you 60 or 80 minutes to complete three or four reading tasks. Before 2011, you would get 20 minutes for the first task, then 40 minutes for the next two, and possibly 40 minutes for a final two. Delta has not updated their material to match the post-2011 test; they still follow the old timing. Besides that, in several reading passages, the number of questions is wrong, at 13 questions where there should be 14. Those two together are a pretty good indication of how carefully Delta has tried to match the current test standards.

Amount of practice material

Yes, there’s a lot of material in this book. But if that’s what you want, buy the book of five official practice tests or possibly the Complete Guide, if you don’t mind spending a little more money. Those would give you practice more similar to the actual test. And if you are looking for full-length tests, in particular, four is not that many—not for a long, intensive TOEFL course, anyway. Cambridge, by comparison, offers seven tests.

Quality of explanations

This is one of the stronger points of Delta: there are explanations to all the reading and listening questions at the back of the book, and there are key points given for each and every speaking or writing task. But the wrong answers are not discussed at all, so if you are confused about why one answer is wrong, the answer key won’t help. For the most part, the explanations just say something like “the correct answer is mentioned at this place of the text….”

As for sample speaking tasks and essays, there aren’t many, and the few that are provided are a bit confusing. In TOEFL practice material, there are two general types of sample answers: “ideal” answers that you should model, and “realistic” answers that give insight as to how to score yourself. Ideal answers are usually from native speakers, and there are no exercises associated with them (such as grading or correcting them). Realistic answers, meanwhile, should sound just like a real student, with all the natural mistakes, accents, etc. Those are great for grading and editing exercises. Delta’s samples are generally native speakers reading from scripts, and some of the actors seem to be using fake accents. There are few or no errors in many of the samples, but you are then asked to “grade” the responses. And that really doesn’t make sense.

Skill building material

Even if it doesn’t do a very good job of it, Delta focuses mostly on giving test-like questions. There are few exercises in this book that train you on skills like note taking, planning essays, or varying sentence structures. There are some, but they’re not a highlight. You could easily use this whole book and not improve your note-taking skills at all. That’s dangerous, because—as I wrote earlier—note-taking skills are really important for the TOEFL.

When it does focus on background skills, Delta generally just explains the skill, gives a short example, and then provides test-like practice material. There is no step-by-step training, like you find in Cambridge.

Academic vocabulary is also strangely missing. There are plenty of idioms and phrases that are listed and defined, but the only list of academic vocabulary is one of prefixes, roots, and suffixes. Some items in that list, like “-polis-,” are linked to words with totally dissimilar meanings (“police,” “metropolis,” “politics”). Learning the meaning of a root like that does not really help you define all the words that contain it. However, the more conversational/general vocabulary that is given is incorporated into test-like exercises, which is a good thing. After all, in order to improve vocabulary properly, you need to learn it in context—not just by a dictionary definition.

I should also mention that Delta really likes transcription exercises. That’s the most notable way that background skills are taught. I’ll be honest, here: I’m not sure how helpful they are for improving listening comprehension. Transcription isn’t very popular nowadays, and most students really don’t like it, in my experience, so I’ve only done it a few times, and only with beginner or intermediate students who are still learning to hear the separation between individual words in natural English. I don’t want to say this is a definite flaw in the book, but I’m skeptical.

Test Strategy and Advice

There are lists of tips sprinkled through the book, but few are very surprising. A lot of the advice is too basic, like this: “During the recording time [in a speaking task], respond to each part of the question. Use key ideas and relevant details from the conversation or lecture to support your points.” I’ve never had a student who didn’t understand that already.

There’s some good, concrete advice in those lists, but most of it is too buried in those unsurprising bits of common sense. And there is very, very little modeling of how to apply the good tips. They’re just listed and then not mentioned again.

Report Card

Authenticity of practice material: C
Amount of practice material: A-
Quality of explanations: C
Skill building material: C-
Test strategy and advice: C+


The Final Word

There is one situation when I would recommend this book: To a student or teacher who cannot spend more money, but has already used all of the official guide, the book of five official practice tests, and free official material. In that case, Delta is comparable to Barron’s.

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7 Responses to Book Review: Delta’s Key to the TOEFL iBT, Advanced Skill Practice

  1. Aline March 24, 2015 at 3:51 pm #

    Hi Lucas, how are you?! I’m from Brazil and I’m preparing to take the Toefl for the second time. I lived in NYC for 6 months last year and there I took my first Toefl exam and scored 79. Not good enough actually, I need AT LEAST 84 to apply to an university I’m aiming.

    Back to Brazil since February, I’ve been studying like crazy (around 8 hours per day) and I was doing good in the practices of the following books (specially in the reading task): Official Guide to the Toefl, Delta’s key, Barron’s and also Speaking and Writing for the Toefl IBT. (I know I sound crazy studying from so many sources, but I really need and want to succeed that time).

    My point is, I’ve scheduled my exam to April 10 and I just bought the Cambridge’s book, which for my surprise I’m scoring really poorly. I don’t know what to do and I got more stressed after your review about Delta’s Key. I feel like I was just wasting my time with that book and now I have no idea how prepared I really am to take again the Toefl.

    I would like to ask you if you have some advice to give me. Like, how can I really measure if I’m read for the Toefl again? Is Cambridge’s book really the closest to the real exam besides the official book? I found the reading too difficult…

    Well, I’m looking forward to your answer! 🙂

    Thank you for all your books reviews. They are really helpful, you have no idea how much you’re helping students like me!! Have an awesome week!

    • Lucas Fink
      Lucas March 25, 2015 at 2:17 pm #

      Hi Aline,

      It sounds like you’re really devoted to increasing that score, which is awesome! Keep it up. 🙂

      First, I should make one thing clear: Cambridge is absolutely not the best source of realistic test material other than the official guide. First, there is the book of five official practice tests. If you want high quality questions like the real TOEFL, that is the best resource. Besides that, The Complete Guide has higher quality practice material than does Cambridge. Note that I gave the authenticiy of Cambridge’s material a B-. It’s better than Delta and Barron’s, but it is definitely not perfect. For one, you’re absolutely right that it’s too hard. The reading questions in particular are poorly written, with debatable answers. I would say that Cambridge has just a few large flaws, whereas other books suffer from more numerous, smaller flaws. In any case, the reason I recommend Cambridge is for the skill-building material, not for the authenticity of the practice tests.

      I don’t recommend judging overall performance by Cambridge’s practice tests. They are good training, but they are not good for measuring your actual TOEFL score. Similarly, it’s not a bad thing that you used Delta’s book. You can learn a lot from it! Understand that these reviews are generally for people who have not bought a book yet. Then it’s better to choose the higher quality books. But if you already have Delta and have used it, that’s not something to worry about. You learned from that book, and you will continue to improve by using Cambridge. 🙂

      • Aline March 25, 2015 at 4:57 pm #

        Hi Lucas!

        Thank you so much for your reply!
        I feel less anxious now that you’ve said that Cambridge’s book is really quite harder than the real Toefl exam. Also, I’ll try to find out if somebody can lend me the book of 5 official tests cuz I can’t buy more books hahaha It would be definitely helpful!

        Actually, I was about to postpone my exam but after reading your feedback, I’m considering again maintaining the date.

        Thanks again!! Have a wonderful week!! 🙂

  2. Rick h September 5, 2018 at 3:07 am #

    I’ve noticed that as I’m skimming the delta book for making my lesson plans (I’ve recently taken over for the previous teacher and am stuck with using her material choice), that there is no reference question mentioned in the reading section. My students will be using the Longman book for at home practice, and I know it is in there, and also in the ets books, but not the delta. Can you think of any reason as to why they would have left out that question type? The skill is really useful for sentence insertion.

    • David Recine
      David Recine September 6, 2018 at 7:27 pm #

      I haven’t had a chance to check out the Delta book myself, but my guess is that the absence of reference questions in the book is simply a mistake. It’s a somewhat less common question type, so the authors and editors may have accidentally forgotten to include it. If it helps, our blog has a quick guide to TOEFL Reading reference questions that you could share with your students and perhaps incorporate into a lesson plan. 🙂

      • Karen February 23, 2021 at 5:07 am #

        What’s you opinion about the delta’s key to the toefl 4th edition? Does it bring new material, or it has recycled content from. this edition?


        • Magoosh Test Prep Expert
          Magoosh Test Prep Expert March 5, 2021 at 10:32 am #

          Hi Karen, I’m afraid we don’t have a full review for this resource yet, so I don’t have an answer to this question.

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