ARTHUR ANDERSEN
REPORT OF INDEPENDENT PUBLIC ACCOUNTANTS
To the Board of Trustees of Calvert Social Index Series, Inc. and Shareholders
of Calvert Social Index Fund:
In planning and performing our audit of the financial statements of Calvert
Social Index Fund (the "Fund") for the year ended September 30, 2000, we
considered its internal control, including control activities for safeguarding
securities, in order to determine our auditing procedures for the purpose of
expressing our opinion on the financial statements and to comply with the
requirements of Form N-SAR, not to provide assurance on internal control.
The management of the Fund is responsible for establishing and maintaining
internal control. In fulfilling this responsibility, estimates and judgments by
management are required to assess the expected benefits and related costs of
controls. Generally, controls that are relevant to an audit pertain to the
entity's objective of preparing financial statements for external purposes that
are fairly presented in conformity with generally accepted accounting
principles. Those controls include the safeguarding of assets against
unauthorized acquisition, use or disposition.
Because of inherent limitations in internal control, error or fraud may occur
and not be detected. Also, projection of any evaluation of internal control to
future periods is subject to the risk that it may become inadequate because of
changes in conditions or that the effectiveness of the design and operation may
deteriorate.
Our consideration of internal control would not necessarily disclose all matters
in internal control that might be material weaknesses under standards
established by the American Institute of Certified Public Accountants. A
material weakness is a condition in which the design or operation of one or more
of the internal control components does not reduce to a relatively low level the
risk that misstatements caused by error or fraud in amounts that would be
material in relation to the financial statements being audited may occur and not
be detected within a timely period by employees in the normal course of
performing their assigned functions. However, we noted no matters involving
internal control and its operation, including controls for safeguarding
securities, that we consider to be material weaknesses as defined above as of
September 30, 2000.
This report is intended solely for the information and use of management, the
Board of Trustees, and the Securities and Exchange Commission.
Philadelphia, Pennsylvania
November 15, 2000
