Misplaced and dangling modifiers
A modifier attaches to whatever the word order puts beside it, whether or not that is what the writer meant. A dangling modifier has nothing in the sentence that it can modify, a misplaced one sits beside the wrong element, and a modifier can also take a grammatical function that does not suit what it modifies. Each fault has its own diagnosis and its own repair.
Modifiers and word order
A modifier is a word or phrase that changes the meaning of some other element in the sentence. Anything that modifies the sense of a sentence should stay close to what it modifies. Words or groups of words should be placed as close as possible to the term they are meant to modify. In Scientists have identified a protein that can increase libido in peanuts, the problem is not a dangler but poor word order, and Scientists have identified a protein in peanuts that can increase libido is one rephrasing that repairs it.
Present participles, gerunds and participial phrases
An English present participle is always formed by adding ing to the stem of the verb, sometimes with minor adjustments to the spelling of the stem, such as dropping the silent e at the end of some words (write, writing) or adding a consonant after a short vowel but not after a long vowel (strip, stripping, but stripe, striping). An -ing word can be used as part of a verb phrase (the dog is barking), as a noun (the barking is a nuisance), as an adjective (the barking dog) or as the head of a participial phrase (barking furiously, the dog scared the burglar). With one or more auxiliary verbs, a present participle expresses the progressive aspect, ongoing action, and a present participle used as a noun is called a gerund. A verb ending in -ing can be a present participle or a gerund, a verb functioning as a noun. Because participial phrases are derived from verb phrases, a participial phrase can include the direct object of a transitive verb (hurling insults), the predicate complement of a linking verb (feeling strong), and the modifiers of the participle and its complement (carefully reading the fine print).
Dangling modifiers
A modifier dangles when whatever it is supposed to modify is missing from the sentence, so that it hangs loose instead of being firmly attached to an appropriate subject, and participial phrases are the most common form of dangling modifier. Dangling modifiers are those that do not correctly modify the subject of the sentence, and the dangling participle is a special case of them. In Walking to school today, my book fell in the mud, the book was not walking, and the participial phrase does not modify any noun or pronoun in the sentence.
Adding the participle's true subject, the appropriate auxiliary verb and a subordinating conjunction to the introductory phrase solves the grammatical problem: While I was walking to school today, my book fell in the mud. That sentence is syntactically correct but does not tell the whole story, and While walking to school today, I accidentally dropped my book in the mud both connects the participle to the correct noun and explains why the book fell into the mud and who was responsible. An editor working on such a sentence would most likely need to query the author to find out how and why the book fell in the mud.
Adding the missing subject to a dangling participial phrase, as in Walking to school today, I dropped my book in the mud, fixes only part of the problem in that sentence. A participial phrase is supposed to be adjectival, describing a noun, but a writer who wants to say how, when or why something happened is modifying a verb, a clause or a sentence and needs an adverbial modifier. One way is to turn the participial phrase into an adverbial clause by adding an auxiliary verb, the participle's subject and the subordinating conjunction while: While I was walking to school today, I dropped my book in the mud.
Dangling participles often form the first word of the sentence: Determining the minimal inhibitory concentrations (MICs) of the antibiotics, the novel compound proved more effective than the comparators implies that the novel compound determined the MICs, when in fact the investigators did. An -ing word that does not tie up with the subject of the sentence creates a dangler that is very likely to distort, if not destroy, the intended message. To avoid one, a writer should ask who or what is doing the action and make sure the implied subject is really responsible for it: The novel compound developed in our laboratory proved more effective than the comparators when we determined the minimal inhibitory concentrations (MICs) of the antibiotics.
Not all danglers are present participles: past participles and prepositional or adverbial phrases can cause similar confusion, as in Based on our findings, the toxicity profile was favorable, With the largest safety margin achieved, we proposed the new formulation for further development and When reviewing the abstracts, it became apparent that…. Most danglers cause a certain degree of confusion and discomfort, and a dangler can usually be exposed by finding the subject of the sentence and applying common sense.
One long-serving journal editor constantly sees dangling modifiers combined with the passive voice to create ridiculous expressions such as Combining the categories and analyzing the data, the results were consistent, where the results themselves could not combine or analyse anything. Dangling modifiers should simply not be written.
Misplaced modifiers and absolute phrases
If a sentence starts with a participial phrase, the phrase will sound as if it is modifying the subject, whether that is intended or not. In Organized into 13 chapters, the reader of this book will benefit from an extensive appendix, an example from an old edition of the AMA Manual of Style, the modifier is not dangling but merely misplaced. The manual's original solution was to make clear that the book, rather than the reader, is organised into chapters, but there is no need to mention the reader at all, and The book is organized into 13 chapters and has an extensive appendix is a better solution.
Many people have trouble telling a dangling or misplaced phrase from an absolute phrase. An absolute phrase does not modify something within the sentence, or even something missing from it; it modifies the sentence as a whole, or perhaps an entire independent clause. It normally contains a noun or pronoun but no true verb, and it may contain adjectives, prepositional phrases, adverbs and participles. His face white with rage, he looked at all of the changes the arbitrary, mean-spirited editor made in his flawless manuscript begins with an absolute phrase, whereas Blushing in embarrassment, he realized that the manuscript he submitted was riddled with errors in syntax begins with a participial phrase that modifies the subject.
On one account, in Based on my experience, English majors make excellent copyeditors, an example from the current edition of the AMA Manual of Style, the introductory phrase is a participial phrase and will not work as an absolute phrase, because it does not contain a noun or pronoun, or even imply one. So the phrase will sound as if it is modifying the subject, and it makes no sense to say that English majors are based on someone's experience. To modify the entire sentence, use a prepositional phrase, as in In my opinion, English majors make excellent copyeditors, or make I the subject: I have found that English majors make excellent copyeditors. The statement that English majors make excellent copyeditors is clearly an opinion, which raises the questions why it is so important to emphasise whose opinion it is, and how the sentence fits in with the general flow of the argument.
A usage columnist classes based on differently, as an absolute construction, one that is unrelated grammatically or syntactically to anything else in the sentence, and notes that many absolutes are dangling participles; other absolute constructions in her account are grammatically speaking, secondarily, considering and judging from. On her account too, based on should not open a sentence, because it could be construed as modifying the subject noun or pronoun: in Based on his scanty knowledge, he believed that global warming is not a threat to the planet, he was not based on his scanty knowledge, and On the basis of his vast experience, he knew that the planet is in great danger avoids the problem. If an absolute is mistakenly linked to the following subject noun or pronoun, the result could be ambiguous and unintelligible at first reading, and the aim should be to make things easy for the reader.
Checking every participle
One way to check every present participle is to use the word processor's find-and-replace feature to highlight every instance of the string ing, which highlights the ing at the end of every English present participle and also the ing in words such as string and stringent, and then remove the highlighting from each word used correctly.
If a highlighted -ing word is the head of a participial phrase, look for the subject of the participle and make sure that the phrase is modifying its subject. A participial phrase can begin a sentence only if the subject of the participle is also the subject of the sentence: Shivering in the cold, he waited for the doors to open. A misplaced participial phrase can end up modifying the wrong noun, because adjectival phrases usually modify the noun that directly precedes them: A woman found the body walking along the path. One fix is to move the phrase so that it directly follows the noun it modifies, as in A woman walking along the path found the body, and in some sentences a comma is all that is needed: He threw a brick at the window, breaking the glass.
If a participial phrase follows a noun, it will seem to modify that noun. In The patients were assigned to treatment groups using a random number generator, a participial phrase used to express how something was done makes it seem that the treatment groups, not the investigators, were using the random number generator. One repair turns the participle into the main verb of the sentence, in the active or the passive voice: We used a random number generator to assign patients to treatment groups, The investigators used a random number generator to assign patients to treatment groups, or A random number generator was used to assign patients to treatment groups. Another adds the preposition by, turning the participial phrase into an adverbial prepositional phrase: We assigned the patients to treatment groups by using a random number generator.
Problems with an -ing verb are usually an ambiguous subject, caused by where it stands in the sentence: at the beginning of a sentence it may not refer to a subject at all, and after a noun it should not refer to, it leaves the reader unsure what its subject is. In Using the survey data, the effects of education on job satisfaction were determined, the implied subject is the researchers and the grammatical subject is the effects; keeping the passive voice, The survey data were used to determine the effects of education on job satisfaction, or changing to the active voice, We used the survey data to…, corrects it. In a school-based intervention using a solution-focused approach, it is not clear who was using the approach, but it was not the intervention, although the placement of using immediately after intervention implies referral to that word.
Misplaced prepositional and adverbial phrases
Put in the wrong place, a prepositional phrase can change from adverbial to adjectival or the reverse, and even a clearly adverbial phrase can end up modifying the wrong thing, so that the sentence does not say what the writer means. A prepositional phrase can act as an adjective, modifying a noun, pronoun or other substantive and answering such questions as what kind or how many, or as an adverb, modifying a verb, an adjective, another adverb, a preposition, a phrase, a clause or a whole sentence and answering such questions as how, when, where, why or how often. A prepositional phrase put directly after a noun will sound as if it modifies that noun, whether that is intended or not: This product is available from Acme Distributors in 10-mL bottles puts the distributors in the bottles, and This product is available in 10-mL bottles from Acme Distributors is better.
Ordinary readers will work out the meaning of that sentence anyway, because they have enough of what artificial intelligence researchers call commonsense knowledge to know that products, not distributors, are found in bottles, though it may take them an extra fraction of a second. Medical writing, however, often deals with things that are not commonplace and about which no one has commonsense knowledge, and there the reader needs every contextual clue the writer can provide.
Even a clearly adverbial phrase can modify the wrong thing if it is put in the wrong place, because adverbs can modify almost anything. In She decided to abstain from drinking after going to church, the adverbial phrase after going to church follows three verbal elements, a past-tense verb, an infinitive and a gerund, and placed after the gerund it sounds as if it modifies the gerund, as though she is still drinking but not on her way home from church. To make the adverbial phrase modify the main verb, put it directly after that verb or at the beginning of the sentence: She decided, after going to church, to abstain from drinking, or After going to church, she decided to abstain from drinking. Both revisions make clear which verb the phrase modifies, but they still explain only when she made the decision, not why she made it or how well she followed through with it, and good technical writing would clarify those issues if they are relevant.
In Few are the teachers who, at the age of five, can teach children to read, the prepositional phrase at the age of five refers not to the age of the teachers, the preceding noun, but to the age of the children, a noun presented after the phrase. Moving the phrase to the end of the sentence, closer to its intended antecedent, avoids the ambiguity instead of relying on the reader to resolve it intuitively. Ambiguous reference chains of this kind often emerge from editing or translating phrases within a larger structure.
A modifier's grammatical function
Knowing the grammatical function of a modifier makes it easier to understand a modifier that misfunctions and distracts, and in turn the options for revising it. In Increased mandibular growth was determined for the animal with the protrusion appliance, it is not clear whether with the protrusion appliance is an adjectival modifying animal or an adverbial modifying was determined, and the underlying cause is the ambiguity of the preposition with. Replacing it with the adjectival past participle treated, as in for the animal treated with the protrusion appliance, explicitly marks animal as what the phrase modifies. The adverbial modification can also be made explicit, with a decidedly adverbial unit such as the preposition-gerund phrase by using the protrusion appliance and with for the animal moved so that was determined is contiguous to by using: Increased mandibular growth for the animal was determined by using the protrusion appliance. This alternative is syntactically plausible, but its meaning is wrong.
The preposition-gerund phrase is so frequent in research writing that treating it as a unique structure seems justified, and it primarily functions as an adverbial, as in Ascorbic acid was determined by using α,α-dipyridyl. In Mutated PTEN that has lost only lipid phosphatase activity failed in mediating repression, the preposition-gerund phrase could be functioning as a modifier of failed, but the intent is failed something, so a nominal is needed as the direct object. The infinitive phrase in failed to mediate repression sounds better, probably because it can function as a nominal and in mediating cannot. In the title The Ability for Synthesising Proline in Streptozotocin-Induced Diabetic Rats, the adverbial preposition-gerund phrase is misused as an adjectival. That phrase and the infinitive phrase in The Ability to Synthesise Proline in Streptozotocin-Induced Diabetic Rats are more animated, but less familiar, than the noun and participle that also function as an adjectival in The Proline-Synthesising Ability in Streptozotocin-Induced Diabetic Rats, whose advantage is its highly thematic focus. Deleting the self-evident ability gives Proline Synthesis in Streptozotocin-Induced Diabetic Rats.
In Raf-1 is a common messenger in mitogenic stimulated signal transduction pathways, the adjective mitogenic is misused before another adjectival: an adjective traditionally modifies a noun, not an adjectival participle such as stimulated. The adverb in mitogenically stimulated is grammatically correct, since adverbs modify an adjective or an adjectival, but it seems a hypercorrection, unfamiliar and stilted. The noun-participle compound adjectival mitogen-stimulated is a familiar type of modifier, and hyphenation reinforces its compound nature. In Lymphedema results in chronic inflammation, fibrosis, infection, and frequently loss of joint function (motion, muscle strength), the adverb frequently is dissonant, because modifying the noun loss requires the adjective frequent; if commas set frequently off, however, it could back-modify the phrasal verb results in.
Displaced and vague adjective clauses
An adjective clause displaced from its modifee, the syntactic unit it modifies, by an intervening syntactic unit is a distraction. Another distraction is the vague adjective clause that seems to refer to an entire sentence rather than to a definite modifee, which has given rise to the pejorative term "vague which". Four examples of these distractions are equally distributed between the results and the introduction of journal articles, indicating a lack of section specificity. A modifier displaced from its modifee distracts by impeding immediate comprehension, whereas a modifier of a whole sentence, because it is conventional, is just a dissonance.
In The appliance resulted in the characteristic tooth movement for control groups, which consisted of three phases, the contiguity of groups and the plausibility of which consisted of as its modifier impede immediate comprehension. Transposing the prepositional phrase, as in For control groups, the appliance resulted in the characteristic tooth movement, which consisted of three phases, makes the adjective clause contiguous to its modifee and lets for control groups function as a sentence orientation. Reducing the clause to the attributive compound adjective in the characteristic three-phase tooth movement is a useful option for its succinctness, though the complete adjective clause, because of its length and its placement at the end of the sentence, is more emphatic.
In There are several methods to estimate the CIR that are more efficient than those previously used, it is not clear whether the adjective clause modifies CIR or methods; the plural that are relates it to methods, but a reader may be uncertain whether the author made a mistake of subject-verb disagreement in number. Transposing the displacing infinitive phrase to the sentence-orientating position, as in To estimate the CIR, there are several methods that are more efficient than those previously used, makes the clause contiguous to methods. Reducing the infinitive phrase to a compound-noun premodifier, as in There are several CIR-estimating methods that are more efficient than those previously used, does the same, and its use may depend on a prior mention of CIR-estimating methods, because it is an attenuated form of methods to estimate CIR.
In Fluid was displaced into the joint cavity, which increased regional synovial fluid pressure, the vague which seems to modify the entire preceding independent clause rather than one specific noun; it could modify fluid, but only the fluid that was displaced into the joint cavity. A displacement that increased regional synovial fluid pressure, the longest revision, gives the clause an explicit modifee in a noun derivative of displaced, but it seems overly obvious, a hypercorrection, and redundant, and it is usually not preferred to the original. The participle in Fluid was displaced into the joint cavity, increasing regional synovial fluid pressure modifies the whole sentence as the clause does, without the backtracking of the relative pronoun which; its tense misagrees with a past observation, but its succinctness and fluidity outweigh its disadvantages, and it is consistently preferred to the other revisions. The compound sentence Fluid was displaced into the joint cavity, and regional synovial fluid pressure was increased befits the two observations but lacks that fluidity. The displacement of fluid into the joint cavity increased regional synovial fluid pressure, with the thematically focused after-the-fact subject displacement, depends on a prior mention in the text and is therefore more appropriate for the discussion section, though it does contain the appropriate past tense.
In Some Alcyonarian soft corals release toxins into seawater, which affect community composition and function, the plural verb indicates that the modifee can be toxins, toxins into seawater or the whole independent clause, and toxins is a likely modifee, so the somewhat awkward transposition in Some Alcyonarian soft corals release into seawater toxins, which affect community composition and function makes the clause contiguous to it. Reducing the clause to the participial phrase in Some Alcyonarian soft corals release toxins into seawater, affecting community composition and function may be preferred, because of its smooth flow, its appropriate present tense for known information and its succinctness, and like the clause the participial phrase is probably modifying the displaced noun toxins. Coordinating independent clauses, as in Some Alcyonarian soft corals release toxins into sea water and thereby affect community composition and function, is the longest revision and makes the two relations explicitly cohere. In The release of toxins into sea water by some Alcyonarian soft corals affects community composition and function, release as the subject is stated after the fact, in the discussion, after the results have stated that the corals release toxins into seawater.
For an adjective clause that modifies a specific modifee, revision eliminates the distance between modifier and modifee, either by transposing the intervening syntactic unit to the start of the sentence or by transposing a premodifier form of the modifier so that modifier and modifee are contiguous. For an adjective clause that modifies an entire sentence, the vague which, the clause can be reduced into a participial phrase or expanded into a coordinate independent clause, and each of the revisions expresses a different nuance.
"Using" and "based on" without a noun to modify
The present participle using and the past participle based on, both traditionally adjectivals, ostensibly misfunction when there is no noun for them to modify, and they are used and misused in research writing often enough to justify analysing them separately.
A participle dangles either before or after an independent clause without an obvious modifee. In Ascorbic acid was determined colorimetrically using α,α-dipyridyl, the participle dangles because ascorbic acid is not using anything, and the dangling results from putting the active sentence Using α,α-dipyridyl, we colorimetrically determined ascorbic acid into the passive voice. Keeping the active sentence would be an unnecessary use of we in a Materials and Methods section, where we is a narrative focus on the agent rather than on the thematic subject, ascorbic acid. Revising to with α,α-dipyridyl supports the hypothesis that using may function as a preposition, for which there seems no dictionary support. Revising to by using α,α-dipyridyl gives a preposition-gerund phrase that functions adverbially by its structure and by its position close to the verb phrase was determined. Requiring by using consistently may seem a hypercorrection and pedantic, because using alone is so common, but by using is unmistakably adverbial and using is not.
Another revision of an adverbial using is syntactic reduction. In The emulsion was forced through a Lipex extruder (Lipex Biomembranes) containing polycarbonate membranes (Nucleopore) at a pressure of 300 PSI using argon gas, the sentence-ending phrase using argon gas overstates a secondary detail. Embedding the detail as the appositional noun phrase in The emulsion was forced (300 PSI, argon gas) through a Lipex extruder (Lipex Biomembranes) containing polycarbonate membranes (Nucleopore) deemphasises it by its length and its parentheses.
The participial phrase in Based on this mechanism, we formulated a model that illustrates the dynamics of holographic grating formation traditionally functions adjectivally, modifying a contiguous noun, which here is not we but model. Transforming the sentence into the passive voice, as in Based on this mechanism, a model was formulated that illustrates the dynamics of holographic grating formation, places modifier and modifee contiguously, resolving the apparent misfunction and eliminating the non-thematic focus on we. A mechanism-based model was formulated that illustrates the dynamics of holographic grating formation melds the orienting phrase and the subject, as a test of the modifier-modifee relation. An adverbial equivalent of based on may be on the basis of, or according to this mechanism, an adverbial prepositional phrase that modifies formulated; being adverbial, such modifiers need not be contiguous to their modifee, though contiguity would reinforce a structure-function pattern.
The adjectival and adverbial misfunction of using and based on results in dissonance. Either participle can be transposed to be contiguous with a modifee, transformed to a decidedly adverbial form such as by using, or replaced with an adverbial unit such as according to.