This is an excerpt from C3's White Paper: "Supply chain visibility: Illuminating the path to responsive, agile operations" by Gregory Braun Senior, vice-president, C3 Solutions.
With everybody talking about it, supply chain visibility has become a buzzword carrying little common meaning. It gets used to mean anything from tracking of containers to inventory control to supplier management and more.
But it is much more than any of these discrete pieces; it encompasses all of them.
"Real-time visibility is more than knowing the location of parts or products along the supply chain. Visibility should also provide you with actionable information that can help support customers, remove redundancies and improve processes," says Jan-Willem Adrian, vice-president of global supply chain and business development at ActiveViam, a company that offers business analytics. 
Using a definition from a 2013 study published in the Journal of Operations Management,  supply chain visibility is: Access to high quality information that describes various factors of demand and supply.
The authors of the study elaborate: "In order for information to be of high quality it must be accurate, timely, complete and useable."  In addition, it must come from multiple sources, including both market level and partner level data. Market level information includes aggregated supply and demand. Partner-level data comes from supply chain partners, both sellers and suppliers. On the downstream, or seller side it includes information such as sales data, demand forecasts and actual inventory positions. Upstream, supplier side information includes inventory levels, lead times and delivery dates, and shipment information.
You may also have heard the term 'control towers' used in relation to supply chain visibility. While this is not an area that we will explore in depth here, it bears noting that research firm Aberdeen describes a control tower as "an end-to-end holistic view of the supply chain and near real-time information and decision making."  (For a look at some of the specific requirements, pitfalls and hype about instant decision-making, this Kinaxis blog is an interesting read).
While having all of this information at your command might seem like the ideal, you can achieve visibility step by step. You don't need the whole big picture at once; gaining insight into operational areas one at a time can deliver immense returns if that data is used proactively to generate decisions that enhance the effectiveness of operations.
1 - "Moving beyond supply chain visibility to continuous decision making", Jan-Willem Adrian, ActiveViam, July 19, 2107. https://activeviam.com/blog/moving-beyond-supply-chain-visibility-continuous-decision-making/
2 - "Leveraging supply chain visibility for responsiveness: The moderating role of internal integration", Brent D Williams, Joseph Roh, Travis Tokar, Morgan Swink, Journal of Operations Management, #31, 2013, p545.
3 - "Supply Chain Control Towers: Defined and Described by Aberdeen", Trevor Miles, 21st Century Supply Chain Blog, blog.kinaxis.com, September 26th, 2012. https://blog.kinaxis.com/2012/09/supply-chain-control-towers-defined-and-described-by-aberdeen/