====== Access Restrictions ======

For each questionnaire in your survey project you can specify who gets access to it. There are five options to do so (see below for details).

  * anyone who knows the link, may fill out the questionnaire (standard setting)
  * participants from a specific IP range only can access (eg. academic or corporate network).
  * you need a password to get access to the questionnaire
  * you can only answer the questionnaire with a individual participation link (serial mail).
  * participants need a unique identifier for participating (serial number).

Access to a questionaire can be defined under:
  * **Compose Questionnaire** -> settings {{:button.settings.png?nolink|}} -> //Access restrictions//.
  * **Compose Questionnaire** -> click your relevant questionnaire -> tab //Access restrictions//.

Choose one option and click //save//. 

You as a project manager can view the questionnaire __at any time__, even if the access is restricted. In order to do so, you click **Compose Questionnaire** or directly in your questionnaire on the green ({{:button.run.gif?nolink|start questionaire}}) or yellow arrow ({{:button.debug.gif?nolink|start questionaire in debug mode}}). When choosing this button you automatically will be recognized as project administrator. This will override access restrictions temporarily and grants you access.

===== public =====

This option will deactivate any access restrictions. The questionnaire will be visible on the internet within the chosen survey period. (choose: **project** -> **project settings**)

Anyone who knows the Internet address (URL) of your questionnaire or finds it (e.g. via search engine) can fill in your questionnaire.

===== serial mail =====

Use access mode //serial mail// if you send your invitations via SoSci Survey by e-mail (s. [[:en:survey:mailing|Sending Serial Mails]]) and thereby use the placeholder ''%link%'' for individualized participation links. 

The personalized links contain a unique code as a unique access code to the questionnaire. Each participant will receive a new subscription code with each invitation or reminder - so participation can be identified for each participant and for each serial mail. 

**Regardless(!)** of the access code SoSci Survey assignes each addressee a subscriber identifier (serial number). This is always being recorded in the data set (variable ''SERIAL'') and allows for multiple serial mails being assinged to responses of various questionnaires. 

**Important:** The participation status of the addressees is  only being recorded (and will be shown under **Send invitations** -> **Address List**) when the access mode of //serial mail// is set.

===== serial number =====

The use of serial numbers is particularly useful when individual participation identifiers are needed - but the mailing of the invitations is not done via SoSci Survey.

A serial number is a one-time password . It entitles you to complete the survey only once (in full). Serial numbers thus ensure that each participant fills out the questionnaire only once (in full). Therefore the participants must be known in advance of the survey.

For SoSci Survey to know which serial numbers are valid, there are two possibilities:

  - SoSci Survey generates through **Send invitaions** -> **serial numbers**, a list of valid serial numbers. These serial numbers will then be communicated to the addressee (outside the program) via your mailing system.
  - You create a list of serial numbers (outside the program) and import these under **Send invitaions** -> **serial numbers** into SoSci Survey.

The serial number appears in the variable ''SERIAL'' in the record. If the assignment of serial numbers to the addressee (by assignement) is known, then the data is not anonymous.

**Tip**: If a questionnaire is being called with a valid serial number, it can be continued even after interview was aborted previously.

Note: Under some conditions, it is possible to complete the questionnaire several times with only one serial number:
  - If the participation status of the serial number is reset by the project manager.
  - If the questionnaire was only viewed (less than 50% of the __actually asked__ questions were answered, see MISSING variable in the data set, [[:en:results:variables|Additional Variables in the Data Set]]).

Serial numbers are different from the participation identifiers in serial mails, among other things because of the fact that they are related only to the addressees -- participation identifiers in serial mails encode both addressee as well as series mail. Therefore, the administration of multi-shaft surveys is a little more complicated: The Project Manager is required to reset the participation status prior to shipment of later invitation waves.
===== Accessible only for specific IPs =====

If you restrict access to the questionnaire on specific IP addresses, then only those persons have access, working on a computer that is connected to the Internet by the specified IP address.

This works the same way access is granted to a chargeable database from a university network. If you want to ensure that only employees and / or students of a university may participate in a survey, then the IP whitelist can be the right solution.

This access restriction mode is useful in case that the IP addresses of the participants are known exactly. Many universities or larger companies have their own IP address or use a specific range of IP addresses. Computers that are installed in companies or that are connected through a VPN to the intranet, use for "outward" communication also these IP addresses.

You can add valid IP addresses as follows. Multiple items can be separated by commas.

  * Individual IP address, e.g.: 192.168.0.1
  * IP address range, e.g.: 192.168.0.20-192.168.0.42
  * wildcard, e.g.: 192.168.0.*

===== Password =====

A classic but less secure solution: You only have access to the questionnaire with one central password.

Since the password is the same for each respondent, this solution is not very secure. The passord can easily be passed around. A lot more secure is the usage of individual access keys (serial mail or serial numbers).

BTW: You can also send the password directly within the link to the questionnaire. That way the respondent does not have to type in  the password manually. (see also: [[:en:survey:url#password_password|URL to the questionnaire]]).

**Important:** When choosing this option you __need__ to specify a passord. Else the questionnaire cannot be filled out by your participants.
===== lock questionnaire =====

If you lock the questionnaire, then you can only have administrator access to the questionnaire. This means you can only start the questionnaire directly through the project administration (**Compose Questionaire**).

