Abstract – Write Like a Scientist

The abstract summarizes the purpose, experimental approach, and principle findings and conclusions of a project. Along with the title, the abstract is published widely (without the rest of the paper) by abstracting services for literature searches, so it must be able to stand alone as a complete picture of your work and concisely give readers enough information to decide if the whole paper might be of interest to them.

Like a title, the abstract is one of the last parts of a paper you should write. This is because you need to know what your methods, results, and conclusions are before you can summarize them in an abstract!

Before you can begin to write your first abstract, it is critical that you get a feel for their scope and level of detail. Read and compare the following abstracts. How are they similar? What structural differences do you notice among them?

“Linked magma ocean solidification and atmospheric growth for Earth and Mars,” Elkins-Tanton (2008) in Earth and Planetary Science Letters:

Early in terrestrial planet evolution energetic impact, radiodecay, and core formation may have created one or more whole or partial silicate mantle magma oceans. The time to mantle solidification and then to clement surface conditions allowing liquid water is highly dependent upon heat flux from the planetary surface through a growing primitive atmosphere. Here we model the time to clement conditions for whole and partial magma oceans on the Earth and Mars, and the resulting silicate mantle volatile compositions. Included in our calculations are partitioning of water and carbon dioxide between solidifying mantle cumulate mineral assemblages, evolving liquid compositions, and a growing atmosphere. We find that small initial volatile contents (0.05 wt.% H2O, 0.01 wt.% CO2) can produce atmospheres in excess of 100 bars, and that mantle solidification is 98% complete in less than 5 Myr for all magma oceans investigated on both Earth and Mars, and less than 100,000 yr for low-volatile magma oceans. Subsequent cooling to clement surface conditions occurs in five to tens of Ma, underscoring the likelihood of serial magma oceans and punctuated clement conditions in the early planets. Cumulate mantles are volatile-bearing and stably stratified following solidification, inhibiting the onset of thermal convection but allowing for further water and carbon emissions from volcanoes even in the absence of plate tectonics. Models thus produce a new hypothetical starting point for mantle evolution in the terrestrial planets. (230 words)

“Heterogeneous heck catalysis with palladium-grafted molecular sieves,” Mehnert, Weaver, and Ying (1998) in Journal of the American Chemical Society:

The synthesis and characterization of palladium-grafted mesoporous MCM- 41 material, designated Pd-TMS11, are described. The material is investigated for carbon-carbon coupling reactions (Heck catalysis) with activated and nonactivated aryl substrates. For the preparation of the new catalyst, a volatile organometallic precursor is reacted in the gas phase with the surface of the porous framework, generating a highly dispersed metal deposition. The ultrahigh surface area, the large pore opening, and the highly dispersed catalyst species in Pd-TMS11 material create one of the most active heterogeneous catalysts for Heck reactions. (88 words)

“The relationship between luminosity and broad-line region size in active galactic nuclei,” Kaspi et al. (2005) in Astrophysical Journal:

We reinvestigate the relationship between the characteristic broad-line region size (R_BLR) and the Balmer emission-line, X-ray, UV, and optical continuum luminosities. Our study makes use of the best available determinations of R_BLR for a large number of active galactic nuclei (AGNs) from Peterson et al. Using their determinations of R_BLR for a large sample of AGNs and two different regression methods, we investigate the robustness of our correlation results as a function of data subsample and regression technique. Although small systematic differences were found depending on the method of analysis, our results are generally consistent. Assuming a power-law relation R_BLR ∝ L^α, we find that the mean best-fitting α is about 0.67 ± 0.05 for the optical continuum and the broad Hβ luminosity, about 0.56 ± 0.05 for the UV continuum luminosity, and about 0.70 ± 0.14 for the X-ray luminosity. We also find an intrinsic scatter of ∼40% in these relations. The disagreement of our results with the theoretical expected slope of 0.5 indicates that the simple assumption of all AGNs having on average the same ionization parameter, BLR density, column density, and ionizing spectral energy distribution is not valid and there is likely some evolution of a few of these characteristics along the luminosity scale. (207 words)

Architecture of succinate dehydrogenase and reactive oxygen species generation,” Yankovskaya et al. (2003) in Science:

The structure of Escherichia coli succinate dehydrogenase (SQR), analogous to the mitochondrial respiratory complex II, has been determined, revealing the electron transport pathway from the electron donor, succinate, to the terminal electron acceptor, ubiquinone. It was found that the SQR redox centers are arranged in a manner that aids the prevention of reactive oxygen species (ROS) formation at the flavin adenine dinucleotide. This is likely to be the main reason SQR is expressed during aerobic respiration rather than the related enzyme fumarate reductase, which produces high levels of ROS. Furthermore, symptoms of genetic disorders associated with mitochondrial SQR mutations may be a result of ROS formation resulting from impaired electron transport in the enzyme. (114 words)

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Audience and purpose

The goal of your abstract is to summarize what the rest of your paper presents in detail. When done well, your abstract should entice interested scientists into reading your paper in full while ensuring that people looking for different information won’t have to search through the full document to realize that it doesn’t contain what they are looking for. This means that the specific context of your work, the types of methods you employed, your major results, and your most important conclusions should all be included in your abstract so that readers can get a complete picture of the work.

This means that your abstract is mostly directed toward experts in your field; but because it contains so many different types of information, its audience also contains other scientists as well as students. This wide array of audience members therefore necessitates the inclusion of both general information, such as the introduction to your project, as well as specific scientific detail in the summarizing of your findings (including quantitative data with errors).

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Style and conventions

There are a few key conventions utilized in the abstract that differ from those in the rest of the paper. Be sure to keep the following differences straight!

1. Avoid using visuals

Although visuals are a very valuable part of the body of your paper, they often take up too much room to be considered useful for an abstract. It is also not appropriate within the abstract to refer to a figure that’s located in the body of your paper; the abstract should be able to stand alone.

The exception to this is if a journal specifically requires that a visual be included, which is occasionally the case in organic chemistry but rarely in most other disciplines. A figure can be useful in the abstract to summarize a procedure or result. In these instances, the visual usually can involve some text for labeling but not a title or caption. Color is often acceptable in the abstract figure.

2. Avoid citing the literature

In most disciplines, literature references in the abstract are discouraged. Although you may refer to information gathered from other sources, it should be general enough to not require a specific citation. If you know that a citation must be used, all of the reference information should be provided in-text so that the abstract is complete on its own (without your Literature Cited section).

3. Avoid using abbreviations and acronyms

Except for very common abbreviations that require no definition, it is better to spell a phrase out completely than to abbreviate it in your abstract. If the term is used repeatedly within the abstract, an abbreviation can be used and defined in order to minimize repetition. However, this term will still require definition again when you first mention it in the body of your paper.

Keeping your abstract concise

Perhaps one of the most important parts of the abstract is that it is concise. Unfortunately, this can also be one of the hardest parts, because summarizing sometimes years of interesting work into a single paragraph means omitting lots of details you find important.

Although there is no universal rule about how long an abstract should be, a good rule of thumb is that it should not exceed about 150-200 words. Luckily, nearly every journal should have explicit instructions for a maximum length for its abstracts.

To learn and practice strategies for achieving conciseness, visit our comprehensive page about the topic here.

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Practice exercise

Edit the following abstracts for conciseness. Try to reduce the abstracts by at least 100 words each.

Adapted from Monthioux et al. (2001):
The presence of impurities in single wall carbon nanotube materials has presented a challenge for their use as-prepared in any of their applications known so far. In an attempt to purify them, single wall carbon nanotube materials subjected to various chemical treatments including a number of regular, published, acidic purification treatments, were investigated by high resolution transmission electron microscopy and X-ray diffraction. Results show that acid purification cannot avoid single wall carbon nanotube structure alteration. The liquid, acidic medium provokes the gathering of pre-existing fullerenes into crystallised fullerite. A slight temperature increase has a dramatic effect on single wall carbon nanotube degradation which can result in complete amorphisation, the process by which something becomes structurally amorphous. The strange piled-up cotton-ball morphology of some nearly amorphous ropes shown in Figs. 17 and 19, in which fullerite clusters were found, might be the result of the surface energetic and kinetic interactions between the transformed material and the liquid environment in which the ropes are immersed during the purification process. Immersion of some of the single wall carbon nanotube materials in dimethylformamide was also found to be harmful to the single wall carbon nanotube structure. Several observations suggest that as-prepared (not treated) single wall carbon nanotubes contain structural defects (including random atomic variances throughout) along the tube walls which act as preferred sites for the acid (or dimethylformamide) attack, inducing side wall openings. (230 words)
Adapted from Riar et al. (2012):
Benghal dayflower is an exotic weed species in the United States that is a challenge to manage in agricultural fields. Research was conducted in North Carolina, Georgia, and Florida to evaluate the longevity of buried Benghal dayflower seeds. Seeds were buried in the field for 2 to 60 mo at a depth of 20 cm in mesh bags containing soil native to each area. In North Carolina, decline of Benghal dayflower seed viability was described by a sigmoidal regression model, with seed size having no effect on viability. Seed viability at the initiation of the study was 81%. After burial, viability declined to 51% after 24 mo, 27% after 36 mo, and <1% after 42 mo. In Georgia, initial seed viability averaged 86% and declined to 63 and 33% at 12 and 24 mo, respectively. Burial of 36 mo or longer reduced seed viability to < 2%. The relationship between Benghal dayflower seed viability and burial time was described by a sigmoidal regression model. In Florida, there was greater variability in Benghal dayflower seed viability than there was at the other locations. Seed viability at the first sampling date after 2 mo of burial was 63%. Although there were fluctuations during the first 24 mo, the regression model indicated approximately 60% of seed remained viable. After 34 mo of burial, seed viability was reduced to 46% and then rapidly fell to 7% at 39 mo, which was consistent with the decrease in seed viability at the other locations. Although there is a physical dormancy imposed by the seed coat of Benghal dayflower, which has been detected in previous studies, it appears that a decline in buried seed viability to minimal levels occurs within 39 to 48 mo in the southeastern United States, suggesting that management programs must prevent seed production for at least four growing seasons to severely reduce the Benghal dayflower soil seedbank. (314 words)

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Solutions

Single wall carbon nanotube (SWNT) materials subjected to various chemical treatments including regular, published, acidic purification treatments, were investigated by high resolution transmission electron microscopy and X-ray diffraction. Results show that acid purification cannot avoid SWNT structure alteration. The liquid, acidic medium provokes the gathering of pre-existing fullerenes into crystallised fullerite. A slight temperature increase has a dramatic effect on SWNT degradation which can result in complete amorphisation. Immersion of some of the SWNT materials in dimethylformamide (DMF) was also found to be harmful to the SWNT structure. Several observations suggest that as-prepared (not treated) SWNTs contain structural defects along the tube walls which act as preferred sites for the acid (or DMF) attack, inducing side wall openings. (118 words)
Benghal dayflower is an exotic weed species in the United States that is a challenge to manage in agricultural fields. Research was conducted in North Carolina, Georgia, and Florida to evaluate the longevity of buried Benghal dayflower seeds. Seeds were buried in the field for 2 to 60 mo at a depth of 20 cm in mesh bags containing soil native to each area. In North Carolina and in Georgia, decline of Benghal dayflower seed viabilities were described by a sigmoidal regression model. Seed viability declined from 81-86% at initiation to 33-51% after 24 mo and <2% after 42 mo of burial. In Florida, there was greater variability in seed viability during the first 24 mo, but a rapid decline in viability was still observed after 36 mo. Although there is a physical dormancy imposed by the seed coat of Benghal dayflower, it appears that a decline in buried seed viability to minimal levels occurs within 39 to 48 mo in the southeastern United States, suggesting that management programs must prevent seed production for at least four growing seasons to severely reduce the Benghal dayflower soil seedbank. (187 words)

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Organization

The abstract is a component of your journal article that is separate from the “hourglass” organization of your paper as a whole.

The organization of your abstract should mirror that of your paper: in general, starting and ending broadly, with important details and data in the middle.

Move structure

The move structure of an abstract is almost like an incredibly condensed version of your paper. You might have one sentence that acts an “introduction,” one that describes your methods, a few that describe your results, and possibly one that acts like a “discussion.” Below is a diagram that outlines each of the moves you should make in your abstract.

1. Describe what your project was about. The first part of your abstract is what informs your audience of the importance of your project. You’ve already given them an idea of the contents of your paper through your descriptive title, but now you are convincing them in one or two concise sentences that it is worth a read. Move 1(iii) is the most critical of the three submoves, but (i) and (ii) are also good to include to help situate the purpose and accomplishments of your project in a greater context.

Below is an abstract from Wallraff et al. (2004). Move 1 is in bold.

The interaction of matter and light is one of the fundamental processes occurring in nature, and its most elementary form is realized when a single atom interacts with a single photon. Reaching this regime has been a major focus of research in atomic physics and quantum optics for several decades and has generated the field of cavity quantum electrodynamics. Here we perform an experiment in which a superconducting two-level system, playing the role of an artificial atom, is coupled to an on-chip cavity consisting of a superconducting transmission line resonator. We show that the strong coupling regime can be attained in a solid-state system, and we experimentally observe the coherent interaction of a superconducting two-level system with a single microwave photon. The concept of circuit quantum electrodynamics opens many new possibilities for studying the strong interaction of light and matter. This system can also be exploited for quantum information processing and quantum communication and may lead to new approaches for single photon generation and detection.

This abstract makes clear the field of research and its importance (submove i). Submoves (ii) and (iii) are more intertwined in the statement: “Reaching this regime has been a major focus of research.” They are saying that no one has yet been able to get a single atom to interact with a single photon (ii) and that they will be attempting to get closer to this goal using cavity quantum electrodynamics (iii).

2. Identify the methods used. The amount of detail you provide in this section is largely dependent on the purpose of your paper. If your goal is to analyze the efficacy of a particular instrument in a specific research context, you will probably need to identify the instrument and the basic experimental outline. If the methods you used are commonplace, you might hardly need more than a word or two to identify them.

Here is the same abstract from above, this time with Move 2 in bold.

The authors decided to describe their experimental design for Move 2. Notice that although the design is clearly complex, they have managed to summarize it in one concise sentence that communicates how this experiment relates to their project goal.

3. Summarize your results. In this move, you show your readers why your paper is important. If there are specific results or trends that are important, you should identify them specifically by saying, for example, “was 4.23 mg/L” rather than “was higher than expected.” Don’t give your readers an exhaustive list of your results, however–choose the most important findings. Finally, you can conclude your abstract with a summary statement of the possible impact of your findings.

Read this abstract again, now taking note of Move 3 (in bold).

The authors begin with submove (i), summarizing the principle findings of their project. They then dedicate two whole sentences to (ii), in which they explain the importance of the system they utilized. This move could probably be improved by adding why the particular results of their experiments are impactful, while condensing their two concluding sentences into one.

Note: Although the moves of the abstract are similar to some of the moves in other parts of your paper (like your introduction and methods, for example), you should avoid directly copying sentences from these sections into your abstract. Instead, take what you know from the paper that you’ve already written and craft new (and hopefully even more concise!) statements for your abstract.

Test yourself

Read the abstract given and identify which sentences comprise each of the major moves (1, 2 and 3) made by the authors. The beginning of each sentence is numbered, such as [1], for easier reference in the solutions.

[1] Sexual reproduction in fungi is controlled by genes present at the mating type (MAT) locus, which exists as two alternative idiomorphs in ascomycetous fungi. [2] The gene content of this locus determines whether a fungus is heterothallic (self-sterile) or homothallic (self-fertile). [3] Recently, a unique sub-class of homothallism has been described in fungi, where individuals possessing a single MAT idiomorph can reproduce sexually in the absence of a partner. [4] Using various mycological, molecular and bioinformatic techniques, we investigated the sexual strategies and characterized the MAT loci in two tree wound-infecting fungi, Huntiella moniliformis and Huntiella omanensis. [5] H. omanensis was shown to exhibit a typically heterothallic sexual reproductive cycle, with isolates possessing either the MAT1-1 or MAT1-2 idiomorph. [6] This was in contrast to the homothallism via unisexual reproduction that was shown in H. moniliformis, where only the MAT1-2-1 gene was present in sexually reproducing cultures. [7] While the evolutionary benefit and mechanisms underpinning a unisexual mating strategy remain unknown, it could have evolved to minimize the costs, while retaining the benefits, of normal sexual reproduction. (Adapted from Wilson et al. 2015).

[1] Seasonal acceleration of the Greenland Ice Sheet is influenced by the dynamic response of the subglacial hydrologic system to variability in meltwater delivery to the bed via crevasses and moulins (vertical conduits connecting supraglacial water to the bed of the ice sheet). [2] As the melt season progresses, the subglacial hydrologic system drains supraglacial meltwater more efficiently, decreasing basal water pressure and moderating the ice velocity response to surface melting. [3] However, limited direct observations of subglacial water pressure mean that the spatiotemporal evolution of the subglacial hydrologic system remains poorly understood. [4] In this study, we simultaneously measured moulin and borehole hydraulic head and ice velocity in the Paakitsoq region of western Greenland. [5] We show that ice velocity is well correlated with moulin hydraulic head but is out of phase with that of nearby (0.3-2 kilometres away) boreholes, indicating that moulins connect to an efficient, channelized component of the subglacial hydrologic system, which exerts the primary control on diurnal and multi-day changes in ice velocity. [6] Furthermore, show that decreasing trends in ice velocity during the latter part of the melt season cannot be explained by changes in the ability of moulin-connected channels to convey supraglacial melt. [7] Instead, these observations suggest that decreasing late-season ice velocity may be caused by changes in connectivity in unchannelized regions of the subglacial hydrologic system. [8] Understanding this spatiotemporal variability in subglacial pressures is increasingly important because melt-season dynamics affect ice velocity beyond the conclusion of the melt season. (Adapted from Andrews et al. 2014).

[1] Isomeric 4′- and 5′-substituted phosphinooxazoline (PHOX) ligands are used to probe the electronic origins of enantioselective nucleophilic additions to (1,3-diphenylallyl)palladium PHOX ligand complexes. [2] Hammett analysis of the 13C NMR chemical shifts of the allyl C-1 and C-3 carbons shows that the major exo diastereomer is less susceptible to differential changes at C-1 and C-3 and that the location of the substituent has a smaller impact on these changes. [3] In contrast, the minor endo diastereomer is more susceptible to differential 13C NMR changes at C-1 and C-3 and the location of the substituent has a greater impact on these changes. The endo diastereomer exhibits a pronounced “cis effect” by the ligating nitrogen and phosphorus atoms across the palladium center that explains its lower reactivity and, therefore, how the enantioselectivity typically obtained with PHOX ligands exceeds the approximately 8/1 ratio of exo to endo intermediates. [4] Swain-Lupton analysis reveals the importance of both resonance and field effects by the substituents regardless of their location and supports the overall electronic control model for enantioselection by PHOX ligands. [5] For rational chiral ligand design and electronic tuning of ligand properties, these results suggest that the overall electronic impact of a remote substituent generally depends more on its identity than on its location within the ligand. (Adapted from Armstrong et al. 2012).

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Solutions

Move 1: Sentences 1 – 3
Move 2: Sentence 4
Move 3: Sentences 5 – 7

Move 1: Sentences 1 – 3
Move 2: Sentence 4
Move 3: Sentences 5 – 8

Move 1: Sentence 1
Move 2: Only parts of sentences 2 and 4. (“Hammett analysis of the 13C NMR chemical shifts of the allyl C-1 and C-3 carbons” and “Swain-Lupton analysis.”)
Move 3: Sentences 2 – 5

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Test yourself

Each of the following sentences are taken out of context from journal article abstracts. Identify the move associated with each statement.

The recoveries of the eight synthetic colorants in four matrices ranged from 93.2 to 108.3%. (Ma et al. 2006)
Here we use P-to-S (compressional-to-shear) converted teleseismic waves observed on several temporary networks in the Central Andes to image the deep structure associated with these tectonic processes. (Yuan et al. 2000)
Dental restorative composites are activated by visible light and the polymerization process, known as direct technique, is initiated by absorbing light in a specific wavelength range (450–500 nm). (Campos et al. 2015)
The effect of repeated treatments with lead on hepatic cell proliferation was investigated in male Wistar rats. (Ledda-Columbano, Columbano, and Pani 1983)
The same conditions were also effective for the synthesis of two trans-porphyrins derived from 5-(2,6-dichlorophenyl)dipyrromethane. (Littler, Ciringh, and Lindsey 1999)
These weak processes are evaluated in an approach which consists of one-nucleon and two-nucleon meson-exchange currents and nuclear wave functions generated by a high precision nucleon-nucleon potential. (Nasu et al. 2015)

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Solutions

Move 3 (Summarize your results)
Move 2 (Describe your methods)
Move 1 (Describe your project)
Move 1
Move 3
Move 2

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