Organizational charts are charts that show a group of employees' relationships to one another. They show who reports to whom, who has a specialist relationship and who is in charge of what tasks. They are good because they give an at-a-glance reference for people who want to know who to talk to about particular issues, but they also have a number of disadvantages.
An organization chart is inflexible; it's a set-in-stone document that needs to be edited, sent to everyone and reprinted whenever there is a change. This is a challenge since organizations are constantly changing. People get promoted, people take on new jobs, people get hired and people get fired, so it can be hard to keep the document up with this chaos.
Focus on Formal
Organizational charts focus on formal communication lines while ignoring informal communication lines. This is a disadvantage because almost all firms function largely on understood and informal protocols. By committing the formal lines of communication to paper, a manager is just driving the informal ones further underground and making them more difficult to recognize.
Organizational charts rigidly define the jobs of the people working at the company. This can be useful, but it is also disadvantageous because people can look at an organizational chart and determine that the responsibilities listed are their only responsibilities. The reality of a workplace, though, is that people often need to do a variety of tasks that aren't necessarily on their job description. Committing jobs to paper makes it easier for employees to say no to reasonable requests.
Organizational charts streamline people into jobs, literally putting them into boxes. This does not always reflect reality. One good example is to compare two people in the same position, for example, as policy analysts. The organizational chart does not reflect the fact that one employee has been in his position for years and shows no notable talent, initiative or influence while the other rose to his position in record time and is very close with a variety of key people in the organization. Looking at an organizational chart, though, makes it look like the two employees are the same.