Article Level Metrics (ALMs) quantify how individual articles are being cited, used, shared and discussed. "Traditional" metrics measure scholarly impact and visibility, while "alternative" metrics measure social visibility. However, ALMs have their own share of limitations. Like journal-based metrics, they may be prone to manipulation and are unable to distinguish between positive and negative attention. 

More information on common ALMs and their limitations is available in the SPARC Primer.  

Citation Count

What is it?

The simplest and most common ALM, Citation Count indicates the number of times that an article has been cited by other research outputs since it was published

Limitations

• Citation count may be different depending on the coverage of the database or tool you use to calculate it. 
• This metric is influenced by many factors that don't necessarily reflect the impact of an article, including publication date and differences in publishing practices across disciplines.
• Citation count may be inflated (either intentionally or unintentionally) by the common practice of self-citation in scholarly research

Field Weighted Citation Impact (FWCI)

What is it?

Field Weighted Citation Impact (FWCI) shows how well an article is cited compared to similar documents in the same field of research. It is calculated as the ratio between the citations received by an article and the average number of citations received by all other similar publications within a particular database.

Limitations

• This metric is calculated based on citation count, and is therefore subject to many of the same limitations.
• Different tools use different methods for calculating FNCI and therefore articles can only be compared based on values provided by the same tool.
• Classifications of subject area or discipline are not always accurate, and this can therefore affect the accuracy of the ranking or percentile. 

Citation Percentiles and Rankings

What is it?

The position of an article compared to other articles in the same discipline, country and/or time period based on the number of citations they have received. Often expressed as a percentile or a “Highly Cited’ label based on percentile rankings.

Limitations

• This metric is calculated based on citation count, and is therefore subject to many of the same limitations.
• Different tools use different methods for calculating citation percentile or rankings. Articles can only be compared based on values provided by the same tool.
• Like with Field Normalized Citation Impact, classifications of subject area or discipline are not always accurate and this can affect the accuracy of the ranking or percentile. 

​Many scholars believe traditional metrics do not give the whole picture of research impact, especially in fields outside the sciences. Alternative metrics use a range of measurements to show research impact. They measure both impact on a field or discipline and impact on society. 

Altmetrics can be useful for early-career researchers, new publications that need time to gain citation counts, or policy documents. They also account for other types of publications, such as datasets, code, or blogging.

Altmetric Attention Score and Donut

What is it?

The Altmetric Attention Score and Donut is a product owned by Digital Science.  tracks mentions of articles and other research outputs such as datasets on social media, news outlets, and bookmarking services. These metrics are visualized using an Altmetric Attention Score and colourful 'donut'. 

• Altmetric Attention Score is an automatically calculated, weighted count of all of the attention a research output has received. It is based on 3 main factors
• The donut visualizes where online attention is coming from. Each colour in the donut represents a different type of online output and includes sources such as policy documents, blogs, news sources, and various forms of social media. 

Limitations

• The Altmetric Attention score does not measure the quality of the research, but identifies the level of online activity. 
• Online attention can be both positive and negative.
• Altmetrics can be gamed, and bots and web crawlers may impact online activity data. 

Where can you find these metrics? 

The score and donut can be found in all products offered by Altmetric, including the free researcher bookmarklet and on many journal publisher websites and repositories (such as Figshare). ​

PlumX Metrics

What is it?

PlumX Metrics is a product owned by Elsevier. This tool provide insights into the ways people interact with individual pieces of research, such as articles, conference proceedings, book chapters and more, in the online environment. These metrics are divided into five categories:

• Citations
• Usage 
• Captures
• Mentions
• Social Media

Limitations

• Usage and Captures don't always reflect the actual number of readers and users of a book or book chapter. For example, someone may download, save or favourite a research output but never actually read or meaningfully engage with it. 
• Altmetrics can be gamed, and bots and web crawlers may impact Usage and Social Media data. 
• As with other ALMs, PlumX Metrics are unable to make distinctions of quality, and online attention can be both positive and negative.

Where can you find these metrics? 

These metrics are incorporated into Elsevier’s research products: Scopus, ScienceDirect and SSRN, as well as Elsevier’s journal and society partner sites.