BMP - Tree Inventories - 31

* Where feasible, require licensed or certified arborists for supervision
or data collectors. This is especially important for conducting basic
tree risk assessments.
* Have the field staff performing the data collection inventory a small
sample containing the same trees and check the results for consistency.
* Make sure that the fields, and the values within them, are clear and
mutually exclusive so that data analysis will be effective and reliable.
* Require an explicit description of field data quality control from the
vendor. The statement should include level and timing of review by
the project manager.
* Where feasible, select a random segment of data early in the process and
have it reviewed by a qualified arborist for accuracy and consistency.
* If possible, have agency staff collect a limited amount of data and
become familiar with the inventory system while the inventory data
are being collected. The staff data collection can be used for verifying
the quality of contractor data collection.

Data Integrity
Data Entry Errors
* If electronic media are not being used for data collection, require a
written procedure for quality control of data entry.
* Check that drop-down lists or other methods are used throughout the
system so that the data will be recorded in a consistent format and
with minimal data-entry errors.
* Inquire about error-checking methods that will be applied to field data.
* Make sure that permission to alter the actual database is appropriately
limited.

Software
* If using an off-the-shelf spreadsheet or database, be sure that sufficient
professional help is available for support.
* Obtain an explicit statement of level and duration of support for commercial packages, including response to software bugs.
* Negotiate the cost of software updates or maintenance releases (e.g.,
version 1.0 to 1.2) of commercial packages and ask for the update
policy, frequency, and costs.
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BMP - Tree Inventories

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