According to the Sawtooth HELP, you need to enter a username and password to gain access to a read-modify or read-only admin module.
See extract from Sawtooth HELP ...
Administrative Module Access
Survey administrators log into the Online Administrative Module using a browser (the login page is studynameadmin.html on the web server) to manage studies in the field and download data. A User Name and Password are required to access the Administrative Module.
This area is used to specify the passwords you use to access the Admin Module. Default user names and random passwords are provided for your convenience (new random passwords are created for each new study), but you can change these if you like.
Lets you provide a name with up to 12 characters.
Lets you provide a password with up to 12 characters (passwords are case-sensitive and can only use numbers or letters). Read-only passwords convey limited administrative rights (e.g. you cannot download the data, delete or accumulate disqualified/incomplete data, edit the passwords file, or reset the survey.)
Lets you provide a password with up to 12 characters (passwords are case-sensitive and can only use numbers or letters). Read-modify passwords convey full administrative rights.
We encourage you to use strong passwords that include a combination of alphabetic and numeric characters, and are at least eight characters long.
I understand Sawtooth v8 has features that enable you to define your own admin module options which is handy. Check out Sawtooth v8 help.
You also have the option of terminating the survey at the end and linking to the admin module directly. You still need to enter the username and password however.